A

The Measuring Devices of Electronics Noise and Its Measurement New Complementary Transistors Make Series Schmitt Circuits Practical Dynamic Notch Filter The Image-Parameter Design of the General Two-Section Elliptic-Function Filter Magnetic Pickup Generates Frequency Markers Tunnel-Diode Delay-Line Simple Method for Plotting Tunnel-Diode Switching Waveforms Novel Feedback Loop Stabilizes Audio Oscillator Design Chart for Con-stant-K Delay Lines Electronic Standards and Measurement Direct-Readin...

Threeterminal Precision Capacitor With Low Terminal Capacitances

In any three-terminal capacitor each terminal of the direct capacitance has a capacitance to ground or shield whose magnitude depends on the type of construction. In addition, when the direct capacitance is variable, these terminal capacitances are usually not constant but change with setting. When such a capacitor is used as a standard in bridge measurements or is measured on a bridge, the terminal capacitances can, if large enough, cause an error in capacitance measurement, which depends on...

Accessories

A 40-dB potentiometer is supplied 20-dB, 80-dB, and linear potentiometers are available as accessories. Accessory motors (50-cyele and 60-cyele) are available for slow-speed and medium-speed chart drive. The slow-speed motors produce chart speeds of 2.5 to 75 in hr, a reduction by a factor of 60 from the speeds available with the standard high-speed motor. The new medium-speed motors, Type 1.521-P23 (60 c s) and Type 1521-P24 (50 c s), are especially recommended for use with analyzers. The...

Actual

2) Add to this a digit component that is 10 times the dialed digit (in kc s), and pass the result on to the input of the next DI-1 unit in the train. This general principle is not new. It was disclosed in print at least as early as 19521 and has been utilized in a number of modern applications.2, 3i 4i 5 However, the grouping of necessary circuits into a train of identical digit units, each of which performs the two listed operations, has made possible the very versatile Types 1161-A and 1162-A...

Additional Stability Parameters

Other factors affecting the short-term stability are temperature, load changes, vibration, and power-supply effects. In general, they are specified separately from the short-term stability data. The effects of temperature can be reduced to acceptable amounts depending only on economics of cost, weight, and power consumption. The most difficult factor is dynamic stability, i.e., the elimination of transient temperature changes much larger than steady-state changes for the same ambient range....

And Decades

Type 1432-Z Decade Resistor (rear). Type 510-H Decade Resistance Unit (left foreground). Type SOO-Y Resistor (right foreground). layer wound on a thin, card-type form. This type of resistor has lower inductance and capacitance than does a spool-wound resistor and, therefore, has much better ac properties. High-valued resistors of this type must use very fine wire if they are to be wound on a form of reasonable size. Recently developed Figure 2. Dimensions of Type 510 Decade-Resistance...

Antenna Patterns

The Type 1521-A Graphic Level Recorder is shown here (Figure 1) at Channel Master Corporation plotting automatically the directivity pattern of a Super-Crossfire antenna. A Selsyn transmitter is mounted on the shaft of the motor that rotates the antenna. The Selsyn receiver drives the recorder through a chain and spur gear (to do this, the gear shift on the recorder must be in neutral, as shown). By choice of gear ratio, the chart can be calibrated in the desired number of degrees per division....

Applications

The wide range of applications of the Type 1396-A Tone-Burst Generator is due to the nature of tone-burst signals, which span the two fields of continuous-wave testing and of pulse or step-function testing. One common application for tone bursts is the testing of transducers in an ambient not free of echoes. The tone-burst test techniques can be used to separate direct and reflected signals and to eliminate standing-wave effects. Examples of this are the testing of sonar transducers in a tank...

Automatic Frequency Control

In one mode of operation of the analyzer, the local-oscillator frequency is controlled by the filtered signal by means of a quartz-crystal discriminator and reactance diodes. When a component has been tuned in, it can be locked by means of this automatic frequency control to stay within the pass band of the analyzer T> ver a wider frequency range than the normal pass band. The characteristics of the control circuit, however, limit the rate at which the frequency can change without dropping...

C

Example of a simple rectifying circuit tested with a tone burst. The reflections produced in a concert hall are determining factors in the acoustical quality of the space. In a test system, a sound source, which may he a pistol shot or a speaker system, is on the stage. A microphone, placed in the seating area, drives the necessary analyzing equipment. Comparisons of pistol-shot and continuous-wave excitation of a hall have shown significant differences in determining reverberation...

Capacitance Bridge

One of the advantages of being a manufacturer of precision measuring instruments is the chance to apply one precision device to the design and production of another. An example is the use of our Type 1G15-A Precision (0.01 ) Capacitance Bridge to measure dimensions of parts of our Type 900 Precision Coaxial Connector to within a few millionths of an inch. The principle of measuring distance by measuring capacitance is based on the relation between the capacitance of an air capacitor and the...

Cations

Thermal protection on transistor heat sink (automatic reset). 0 to 1.0 for continuous operation to 30 C ambient. 0 to 1.0 for intermittent operation to 50 C ambient. 0.7 to 1.0 for continuous operation to 50 C ambient. Meters 0 to 5, 15, 50, 150, 500 volts. 0 to 0.05, 0.16, 0.5, 1.6, 5 amperes. Power Requirements 1 05 to 1 25 (or 21 0 to 250) volts, 50 to 60 cps, 70 to 500 watts, depending on load. For 50-cycle supply, maximum output must be reduced 20 . Sensitivity Approximately 2 volts needed...

Circuits

The basic bridge circuit, Figure 2, is familiar to anyone who has taken freshman physics. It differs from the simple Wheatstone bridge circuit in two ways T-networks are used in the ratio arm, Rs, on the top ranges, and a AR adjustment can be inserted in the fixed arm, RP. One should also note that the main adjustment arm is the arm opposite the unknown, so that A Bridge to Teraohm Territory CONTENTS AC Power Supply for the Vibration Meter OF Coaxial U-Line Section THIS ISSUE Relay-Rack Mount...

Coaxial Connectors At Dc

DC TO MICROWAVE That's the frequency range covered by Type 874 Coaxial Connectors. And for critical measurements at dc the positive contact, good shielding, and convenient plug-in features of the connector are just as important and useful as at microwave frequencies. An excellent example of dc use is provided by the accompanying photograph which shows these connectors in a test chamber at Spaulding Fibre Company of Tonawanda, New York. In this photograph, samples of Spauldite laminates are...

Component

The linear frequency scale, the three bandwidths, and a high-level, 80-db-dynamiorange output make the combination of a Type 1521 Graphic Level Recorder and Type 1900-A Wave Analyzer a recording analyzer of outstanding usefulness. Another output for use with 1-ma dc recorders is also included. The analyzer also functions as a tunable filter, and it has a generator output that tracks the tuning of the analyzer, thus providing both a power source and a tuned-voltmeter detector for network...

Convenient Generatordetector Unit For Bridge Measurements

The Type 1232-A Tuned Amplifier and Null Detector 1 and the Type 1311-A Audio Oscillator2 have been combined in a single, convenient unit for use with audio-frequency bridges and other null-balance devices. This new assembly, the Type 1240-A Bridge Oscillator-Detector, occupies a minimum of bench space and is provided with removable panel extensions, which adapt it for rack mounting. The combination can also be easily disassembled so that component instruments can be used separately. The...

Correction

Several eagle-eyed readers have pointed out that the schematic of a pulsed bias supply for use in transistor measurements (Experimenter, February, 1964, page 7) shows that the bias source is shorted when the relay operates. This is quite true, but, as used by Clark Division, National Semiconductor Corporation, who devised the circuit, the shorting does 110 harm since they use a constant-current bias supply, rather than a battery. We apologize to our puzzled readers for omitting this fact. ,

Counters

The new, improved Type 1150-B Digital Frequency Meter (10 cps to 400 kr) and the Type 11.) -A Digital Time and Frequency Meter (dc to 400 ke), supplemented by the Type 1136-A Digital-to-Analog Converter and the Type 1137-A Data Printer. See Ex-perimenter, April, 1902. June, 1963, and December, 1963. TYPE 1025-A Standard Sweep-Frequency Generator A standard-signal generator with swept-frequency or cW output accurately known output voltage marker calibrated and adjustable in frequency and...

CYCLES

Figure 13. 3-eycle pass band of he Type 1900-A Wave Analyzer recorded by the Type 1521-B Graphic Level Recorder, equipped with an experimental plug-in for generating a sweeping voltage. Frequency markers were generated automatically by use of the circuit shown in Figure 12. and markers thus occur at 1-cycle intervals. The sweep width is the same as in Figure 3a. In Figure 3c, the only change is that the button under X 10 CPS has been pushed, so that the sweep width and marker spacing are 10...

Decade Frequency Synthesizers

Figure la and Figure lb show the two GR synthesizers. The physical resemblance is no accident the units are designed to be nearly identical. In fact, one can be transformed into the other by the change of one plug-in module. Figure lb. The Type 1161-A Synthesizer is similar in appearance to the Type 1 162-A. Figure lb. The Type 1161-A Synthesizer is similar in appearance to the Type 1 162-A. The Type 1161-A Coherent Decade Frequency Synthesizer provides any desired output frequency from dc to...

Description

The Type 1900-A Wave Analyzer is a heterodyne type of analyzer. As can be seen from the block diagram, Figure 2, the main filter is a 100-kc quartz-crystal filter. Any frequency in the range from 20 to 54,000 cps can be heterodyned with the local oscillator, which is tunable from 100 to 154 kc, to produce a 100-kc difference frequency, which is applied to the filter. The amplified output of the filter drives a metering circuit and supplies a voltage for recording. This basic analyzing system is...

Distortion Oscillator

We have received a number of inquiries for the Type 1301-A Low-Distortion Oscillator, and we are glad to announce that this instrument is still available from stock. The Low-Distortion Oscillator provides push-button selection of 27 fixed frequencies between 20 and 15,000 cps. These are the recommended test frequencies for audio distortion measurements in radio-broadcasting stations. This oscillator and the Type 1932-A Distortion and Noise Meter comprise a system for the fast and accurate...

Qur

Figure 8 is a plot of the first thirty-one harmonics of the above signal. Figure 9 shows, as a second example, the first, t hirty-one harmonics of an eightr-cyele-on, eight-cycle-off tone burst. The t wo curves were taken from an automatic plot of the frequency spectrum produced by using a General Radio Type 19()0-A Wave Analyzer and Type 1321 Graphic Level Recorder. In the two examples the tone burst-had N M, for which case the amplitudes are zero for even values of n (except zero). Therefore,...

Emergency Power

A nickel cadmium battery of 4 am-pere-hours is floated across the dc supply. The cells of this battery are of the pressure-relief type and cannot explode. In case of power-line failure, operation for 35 hours is ensured at room temperature and up to 24 hours at 0 C. An external dc supply of 22 to 35 volts can also be used. If ac power, external dc, and internal battery are connected, the power will be drawn from the source that provides the highest voltage to the regulator circuit. The...

Experimen

1964 GENER AL RADIO COMPANY, WEST CONCORD. MASS., U.S.A. Published Monthly by the General Radio Company VOLUME 38 NUMBER 2 FEBRUARY 1964 GR's New Bolton Plant 3 The Precise Measurement of Small Dimensions by a Capacitance Bridge 4 New, Megohm, Wire-Wound Resistors and Decades . 5 Measurements on Power Transistors with the Transfer- Function

Experimenter

1964 GENERAL RADIO COMPANY, WEST CONCORD, MASS., U.S.A. Published Monthly by the General Radio Company VOLUME 38 NUMBER 1 JANUARY 1964 A New 200-VA Audio New GRO Representative for Greece 8 Operation of Variac Autotransformers on 208 1 20-Volt Coaxial Connectors at The General Radio EXPERIMENTER is mailed without charge each month to engineers, scientists, technicians, and others interested in electronic techniques in measurement. V hen sending requests for subscriptions and address-change...

Feedback Amplifier

The output circuit will pass up to 5 amperes of dc. The generator is an excellent power source for the measurement of the properties of ferromagnetic materials with the Type 1633-A Incremental-Inductance Bridge at high levels of ac and dc excitation. Other uses include driving shaketables and acoustic transducers, testing servo systems and magnetic amplifiers, and testing regulated power supplies. For specialized testing, the power amplifier can be driven from an external source, such...

Frequency In Cycles Per Second

Low-frequency response of the Graphic Level Recorder for various positions of the low-frequency cutoff switch. 20 c s, less than 1 dB down at 7 c s, and 3 dB down at 4.> < s (see Figure 2). This extended low-frequency response requires a greater detector time constant, reducing the ability of the recorder to follow rapid changes In level. Therefore, writing speed and detector time constant are switched together, so that the user can improve low-frequency response at the expense of...

Frequency In Kc

Charts of modulation noise on a l-kc tone for two different types of magnetic tape. Note thai one is about 10 db better than the other. Such measurement can be made easily with the recording analyzer, owing to the 80-db dynamic range. For these records, chart speed was 2.5 inches per minute writing speed, 10 inches per second bandwidth, 10 cps. signal is analyzed, the recorder's fastest writing speed should be used to speed up the recording. Its fast writing speed makes the Type 1521...

Frequency

The frequency is indicated on a counter and a dial with a linear graduation, 1 division 10 cps. Accuracy of Calibration (3 2 +5 Cps) Up to 50 kc 1 beyond 50 kc. Incremental-Frequency Dial (AF) 100 eps. Accuracy is 2 cps below 2 kc, 5 cps up to 50 kc. Automatic Frequency Control At frequencies below 10 kc, total range of frequency lock is 400 cps for the 50-cycle band and 150 cps for the 10-cycle band, as defined by 3-db drop in response from full-scale deflection. At 50...

From Side Marker

The monitor frequency from the beat terminals is measured or recorded. As the synthesizer output frequency varies in response to changes 111 the unknown frequency, the beat output varies proportionately, at what may be a very highly magnified rate, depending upon which button has been pushed. For example, if the drift is small, the X 1 CPS button might be used. In this case, a change of 1 c s in the synthesizer output would produce a 10-kc change in the recorded beat frequency a magnification...

Gated Signal Output

Gate-Open Output Maximum signal level is 7 volts. Total distortion is less than 60 db (compared to maximum level) at 1 kc and 10 kc. Gate-Closed Output Less than 140 millivolts, peak-to-peak, ( 40 db) with maximum signal input. Pedestal Output (dc potential difference between open- and closed-gate output) Can be nulled from front panel. Less than 50-niillivolt change with line voltage. Switching Transients Less than 140 millivolts, peak-to-peak, ( 40 db compared to maximum signal input). GATING...

General

Ambient Operating Temperature 0 to 50 C (32 Power Requirements 105 to 125 (or 200 to 240, or 210 to 250) volts, 50 to 00 cps, 15 watts, approximately. Accessories Supplied Type CAP-22 Power Cord. Accessories Required External source for any desired frequency range between 0 and 500 kc. Cabinet Bench type with rubber feet. Front feet are extendible to tilt cabinet. Dimensions Width 8, height 5 , depth 7K inches (205 by 150 by 195 mm), over-all. Net Weight 6 2 pounds (3 kg). Shipping Weight 10...

General Radio Company

Telephone (Concord) 369-4400 (Boston) 646-7400 Area Code Number 617 METROPOLITAN Broad Avenue at Linden, Ridgefield, N. J., 07657 NEW YORK * Telephone N. Y., 212 964-2722 Pickard Building, East Molloy Road, Syracuse, N. Y 13211 1150 York Road, Abington, Pa., 19001 WASHINGTON* Rockville Pike at Wall Lane, Rockville, Md., 20852 and BALTIMORE Telephone 301 946-1600 113 East Colonial Drive, Orlando, Florida, 32801 6605 West North Avenue, Oak Park, Illinois, 60302 2501-A West Mockingbird Lane,...

Generator

The Tone-Burst Generator is a unique instrument, which, when fed from an external oscillator, generates pulses, or bursts, of the input frequency. It is useful for testing the time response of ae circuits and for simulating the pulsed ac signals commonly used in audio and ultrasonic equipment, such as sonar. In addition to its many applications in the direct measurement of sonar transducers and amplifiers, it has been used as a generator for bridge measurements where high peak power is needed...

Graphic Level Recorder

Experience with the Type 1150-A Digital Frequency Meter 1 and with the circuitry of its more sophisticated brother, the Type 1151-A,2 has made possible a number of improvements that increase reliability, ease of operation, and frequency range. A new model, the Type 1150-B, now replaces the original A-model. This digital frequency meter is based on the same simple, economical ring counting units used in its predecessors. The upper frequency limit, however, has been raised from 300 kc s to 400 kc...

Harmonic Numbers

Quency (the third harmonic), and so on, indefinitely. The amplitude of each component in the above series is given by - b n+M y j - (ct +i) i K the amplitude of the signal being gated. The values of N and M are on the Tone-Burst generator controls. When x or y equals zero, the two fractions involved assume indeterminate forms, but the proper value of the fraction under these conditions is one. As an example of the use of these equations, consider a tone-burst signal having one cycle on and one...

In This Issue

Bridge Oscillator-Detector Inductance Measuring Assembly Stage-Lighting Control crystals 1 developed by Bell Telephone Laboratories. Their ultimate aging rates are less than 1 in 1010 per day for the 5-Mc unit and less than 1 in 10u per day for the 2.5-Mc. The choice between the two frequencies is generally dictated bjr cost and convenience. The 2.5-Ale crystal is twice as large as the 5-Mc and much more expensive in addition, for comparable performance, it requires better (dynamic) temperature...

Increased Frequency Range For The Type A Digital Time And Frequency Meter

The Type 1151-A Digital Time and Frequency Meter 1 measiires frequency, frequency ratio, period, and multiple 1R. W. Frank, Zero to 300 kc with Five-Digit Accuracy, General Radio Expei .' enter, 37. 6, June, 1963. periods and is equipped with a full complement of input controls. Its guaranteed upper frequency limit, formerly 300 kc s, has been increased to 400 kc s, with no increase in price.

Inductance Measurement

Panel view of the Bridge Oscillator-Detector Assembly. For the precise measurement of inductance and the intercomparison of inductance standards, the Type 1632-A Inductance Bridge 1 offers both accuracy and convenience. Its wide range of inductance, from 0.0001 h to 1111 h, embraces a variety of applications. It can measure rf coils at 1 kc (where stray capacitance is not a factor) to an accuracy of 0.1 . It can compare two 10-henry standard inductors at 100 cps to a precision of 1 part in 105....

Info

A peak-responding instrument accurate to 2 of indication not full scale) usable up to 1500 Mc ( 2 db). Ac, dc, and ohms scales voltage scale is logarithmic. Probe is new design, with accessory tips, ground clips, etc. Available in Flip-Tilt case or on relay-rack panel. See Experimenter, July 19G3. A precision R-L-C-G bridge with 0.1 accuracy, digital readout, automatic decimal-point location, and illuminated indication of the units of measurement. Internal oscillator and detector for 1-kc...

Input

Voltage Range 30 microvolts to 300 volts full scale in 3, 10 series. A decibel scale is also provided. Voltage Accuracy After calibration by internal source, the accuracy up to 50 kc is (3 of indicated value -f- 2 of full scale) except for the effects of internal noise when the attenuator knob is in the maximum-sensitivity position. in that position the internal noise is about 5 of full scale for the 3- and 10-cycle bands and 10 of full scale for the 50-cycle...

Input Circuit

The input control for the instrument is a constant-input-impedance, 1-megohm attenuator. A 54-kc low-pass filter in the input amplifier reduces the response to signals beyond the operating frequency range of the instrument. This filtering is essential to minimize responses at the 100-kc filter frequency and at image frequencies. These responses could otherwise lead to serious errors, particularly in the measurement of wide-band noise. Figure 3 (right). Filter characteristics for the three...

Local Oscillator

The oscillator uses the series-tuned Vackar circuit1 with a large, high-Q, universal-wound coil and stable capacitors to achieve a high degree of frequency stability. The frequency-control capacitor of the oscillator is shaped so that the frequency is a linear function of the dial rotation. The linear scale makes possible the use of a combination of dial and counter to get high resolution and an in-line readout. But, more importantly, when the analyzer is tuned manually, this linearity makes...

M

Source fitted with a male 3-terminal microphone connector. Input impedance is approximately 13 Mi2 in parallel with 25 pF. For correct weighting, source impedance must be 380 pF 5 . Power Supply One 1 J- -V size C flashlight cell. Battery life approximately 35 hours for 2 h day service. Operating Temperature Range 0 to 50 C. Storage Temperature Range - 20 to + 70 C (battery removed). Operating Humidity Range 0 to 90 RH. Temperature Coefficient of Sensitivity -f- 0.03 Sensitivity to Magnetic...

Main Amplifier And Weighting

Two amplifier stages and a power supply. Transistors Q101 and Q102 comprise the preamplifier. Q101 is a special N-channel field-effect transistor, operating as a source follower. The gain of the second transistor (Q102) can be adjusted by means of a panel screwdriver control to calibrate the instrument. The main amplifier uses four transistors, including a complementary pair (Q105 and Q106) at the output. Feedback is applied to the emitter of transistor Q10S to stabilize voltage gain. This...

Motors

1521-P19 (high-speed, 60 c s) for paper speeds of 2.5 to 75 in min 1521-P21B (high-speed, 50 c s) for paper speeds of 2.5 to 75 in min 1521-P23 (medium-speed, 60 c s) for paper speeds of 0.5 to 15 in min 1521-P24 (medium-speed, 50 c s) for paper speeds of 0.5 to 15 in min 1521-P20B (low-speed, 60 c s) for paper speeds of 2.5 to 75 in hr 1521-P22 (low-speed, 50 c s) for paper speeds of 2.5 to 75 in hr 59.00 65.00 59.00 65.00 59.00 65.00

New Dial Decade Resistors

Two new six-dial models have been added to the GR line of Type 1432 Deeade Resistors, one with steps of one ohm, the other with steps of 0.01 ohm. Housed in the laboratory-bench-style aluminum cabinets that are characteristic of the Type 1432 series, these new decade boxes have 11-position rotary switches with silver-overlaid contact studs on the low-resistance decades to ensure stability of resistance. All decades have a silver contact in the zero position in order that the zero resistance of...

New Members Of

As the GR900 precision coaxial connector gains rapidly in popularity, we are striving to meet the great demand for elements based on this coaxial design. Among those to be introduced at WESCON are The Type 900-TUA Tuner, used with the Type 900-LB Precision Slotted Line to cancel out residual reflections of rf terminations, measuring instruments, connectors, and adaptors at frequencies between 1 and 9 Gc s. The tuner comprises a section of 50-ohm coaxial line with three adj ustable tuning screws...

New Onemegacycle Counter

A new 1-Mc counter has joined the ranks of GR's fast-growing line of digital frequency equipment. The Type 1150-BH Digital Frequency Meter is similar to the 400-kc Type 1150-B1 in all respects except frequency range. In other words, it is a trim (33 inches high in a relay rack), economical, solid-state counter with crisp, bright, incandescent readout. Counting time can be set to 0.01, 0.1, X, or 10 seconds, and display time 1 r.w. Frank, 400-kc Solid-State Counter. General Radio Experimenter,...

New Wave Analyzer Has Bandwidths Db Dynamic Range

The new Type 1900-A Wave Analyzer, shown in Figure 1, is one of the most versatile measuring instruments ever devised. In its primary function as an electric-wave analyzer or selective voltmeter over the range from 20 to 54,000 cps, it provides three different bandwidths 3, 10, and 50 cps and a wide sensitivity range to cover a variety of spectrum-analysis requirements. Its three meter speeds, together with the three bandwidths, make it exceptionally useful for noise analysis.

Noise Analysis

The new analyzer is well suited for the analysis of noise. The slow meter response is one essential feature, and the choice of bandwidths and the linear frequency scale simplify many noise analyses. Three different meter speeds are provided. The fastest time constant is essentially that of the meter alone, about second. This speed is always used for measurement of components of periodic signals. The slowest time constant provided is about 5 seconds, and this and the intermediate value are used...

O

Stability Prf and pulse-duration jitter are dependent on power-supply ripple and regulation. With Type 1201 Power Supply, external-drive terminals short-circuited, prf jitter and pulse-duration jitter are each 0.01 . With Type 1203 Power Supply, they are 0.05 and 0.03 , respectively. (Jitter figures may vary 1 -pts pulse into 50 ohms with delayed sync pulse. 1 -pts pulse into 50 ohms with delayed sync pulse. Among the great time savers of recent invention was the GR Type 1559-A Microphone...

Oii Unit

Signal traversing a typical Digit-Insertion Unit. accurately against a reference or, if the synthesizer is phase-locked to an external standard, to adjust for optimum locking conditions. The other screwdriver control operates a switch that changes the normal ac-coupled output circuit to dc coupling. With dc coupling, the output frequency can be adjusted as low as desired, down to dc, but the output voltage available is only about 1 volt, rms. The output voltage monitor meter is...

On Volt Lines

Users of Variac autotransformers should seriously consider the advantages inherent in the increasingly popular 208 120-volt, 3-phase distribution system. Because the wye voltage of this system is 120 volts (rather than 139 volts as in a 240-volt system), certain restrictions on Variac autotransformers in 3-phase circuits no longer apply. The 208 120-volt, 60-cycle system allows the use of Types W5L and W8L other models can be connected for overvolt-age, or step-up, as shown in the accom panying...

OO

E(t) the tone-burst voltage. a the amplitude of the nth component, n harmonic number (1, 2, 3, 4, etc.). N - number of cycles of signal in the burst (open count in the Tone-Burst Generator). M number of cycles (periods) of signal between bursts (closed count in the Tone-Burst Generator). T the period of the signal being gated. The sine series is used if the signal is gated on and off at zero crossings, and the cosine series if gating is at the peak point of the sinusoidal input voltage. The...

Operating Principles

The principle of the I Jigit-Insertion Unit is the dual of that of the familiar error multiplier sometimes used to magnify small frequency differences by successive subtractions and multiplications. In the Digit-Insertion Unit, in contrast, we add and divide, to manufacture small differences. As shown at the right of Figure 8, the total input signal to a digit unit lies between 5 and 5.1 Mc s. To this is added 42 Mc s generated coherently from the master crystal oscillator. To the resulting...

Oscillator And

The effects of component changes on the frequency of a crystal oscillator have been analyzed in the past.8 Figure 11 shows the basic arrangement of the crystal network and oscillator circuit. For the 5-Mc, oth-overtone crystal, a 1-pf change of Ci or C2 (0.3 ) amounts to a frequency variation of about 5 X 10-10. The shunt capacitances Ci and C2 are about 330 pf each, and this network requires a transconductance of 1 5 milliamperes per volt to sustain oscillations. Such a transconductance would...

Oscillator Circuit

Mon-sense utilization of tubes and transistors to exploit the strong points of both. The main components of the pulse generator are an input system, a pulse-timing circuit, and a power amplifier. Switched for internal control of prf, the input system is a stable, wide-fre-quency-range oscillator. Switched for external control, the circuit becomes an aperiodic trigger generator, made up of a dc amplifier and a Schmitt trigger. This circuit produces a single, brief, trigger pulse to initiate the...

Oscillators

In the measurement of physical quantities, the demands of science, industry, and the military are for constant improvement in accuracy. Standards and measuring devices, as a result, must meet ever tighter specifications. This trend is well illustrated by Figure 1, which shows the increase in accuracy of the U. S. Frequency Standard over a period of some 40 years. Atomic frequency control, which is used in the U. S. Frequency Standard, provides bot h the best accuracy and the best long-term...

Other Factors Affecting The Frequency

Temperature control of the crystal and other critical components keeps the over-all temperature coefficient typically less than 5 X 10 12 C. Transient response is such that frequency excursions stay within the specified steady-state limits for sudden changes in temperature over the range of 0 to 50 C. Loading effects have been reduced to negligible amounts by careful arrangement of ground loops. Very little output is fed back into the oscillator, as evidenced by the fact that tuning of the...

Output

Power 200 voltamperes, 50 cps to 1 kc. (See curves on cover.) Full-Scale Output Ranges 4, 12.5, 40, 125, 400 volts, rms 0.5, 1.6,5 amperes in any combination up to 200 va. Optimum Load Impedance 0.8, 2.5, 8, 80, 800 ohms. Will operate satisfactorily with higher-impedance or nonlinear loads. Output transformer will pass dc equal to rated ac. Regulation and Response Time (See cover.) Less than 20 no load to full load-20 cps to 1 kc. (Bandwidth greater than 10 kc provides essentially instantaneous...

Output Pulse

Schematic diagram of timing and output circuits. Transistors QIOI and Q 02 are connected in a bistable circuit to control conduction of the output power tubes, VIOi and VI06. Such hybrid design exploits strong poihts of both tubes and transistors. form at the output terminals depends on the termination. In Figure 2, the terminating resistance is 50 ohms. All transition times are less than 10 nanoseconds, and some overshoots occur. With no external loading, the very fast current...

Outputs For Recording

The new analyzer Jias a number of outputs, two of which are specifically provided for recording purposes. The most important is the 100-kc filtered-and-amplified signal for driving the Type 1521 Graphic Level Recorder. This output has an 80-db dynamic range and enough power so that the full capabilities of the recorder can be utilized, and the recorder and the analyzer, shown in Figure 4, make a remarkably useful combination, which

OVEN

A single-stage oven with proportional control holds the temperature of critical components within less than 10 milli-degrees C. Power consumption of this oven was considered important because of battery operation in case of line failure. The power consumption is only about 500 milliwatts for operation at room temperature. The insulation of the oven is a combination of a Dewar flask and polyurethane foam, in which the flask is completely embedded. This assembly has survived shock tests of 50...

Panel Controls

As may be seen in Figure 1, eight frequency-setting dials, with illuminated numbers on seven of them and a continuously calibrated scale on the eighth, provide an in-line readout of the synthesized frequency to nine or more significant figures. Behind each dial is a digit unit. The signal flows through this synthesizing portion of the instrument from right to left, enter Below each digit dial is a pushbutton. When one of these buttons is pushed (and automatically latched), an rf switch behind...

Philadelphia Office Moves

Our Philadelphia Sales Engineering Office has just moved a few miles west into brand-new quarters at Fort Washington Industrial Park, adjacent to the Pennsylvania Turnpike at Fort Washington, Pennsylvania. The new diggings are larger than the old and include better parking facilities, all the better to accommodate the burgeoning business at PHO. The numerology of the situation is as follows phone number 215-646-8030, TWX number 215-646-7996, and Zip Code 19034. Manager John Snook and Sales...

Pulse Repetition Frequency

Internally Generated 2.5 c s to 1.2 Mc s, with calibrated points in a 1 3 sequence from 10 c s to 300 kc s, and 1.2 Mc s, all 5 . Continuous coverage with an uncalibrated control. Externally Controlled Aperiodic, dc to 2.4 Mc s with 1 V, rms, input (0.5 V at 1 Mc s and lower) input impedance at 0.5 V, rms, approximately 100 kS2 shunted by 50 pF. Output pulse is started by negative-going input transition. OUTPUT-PULSE CHARACTERISTICS Duration 100 ns to 1 s in 7 decade ranges, 5 of reading or 2...

Quartzcrystal Filter

The use of four low-temperature-coefficient quartz crystals has made possible the development of a filter that can be switched to three different band-widths and which has excellent characteristics over a relatively wide range of ambient temperatures. The band-widths selected are 3, 10, and 50 cps, which are adequate for almost any analysis problem. Typical response characteristics are shown in Figure 3. The importance of being able to select any one of three bandwidths is easily demonstrated...

Recording Assemblies

End frames and rack supports supplied for bench or relay-rack mounting. Type 1521-B Graphic Level Recorder with me- dium-speed motor and recorder accessories Type 1521-9464 Chart Paper, 10 rolls Type 1521-9465 Chart Paper, 10 rolls Type 1521-P3 80-dB Potentiometer (inaddition) to 40-dB Potentiometer included with recorder) Type 1560-P95 Adapter Cable (phone to double plug)

Reprints

Reprints are available of a number of articles by General Radio engineers published in technical journals. Recent papers include Phase-Locked Oscillator A-80 VHF Matching Network Design A-81 A New Design Procedure for Optimum Matching Networks -< A-82 A Novel Method of Frequency Multiplication -83 A Standard Program Cuts Costs A-84 Design Trends Increase Versatility of Standard-Signal Generators that Humans Can Read A-86 Plastic Cutouts Help Design C Boards A-87 Mixer Circuit Has Clean Output...

September

The term frequency synthesizer can quite properly be applied to any of a variety of devices. For instance, a type of radio transmitter widely used for aircraft communications synthesizes a large number of channels by combining frequencies selected from groups of independent crystals. Such synthesizers are not frequency coherent, since the output frequency reflects the individual errors of several crystal oscillators. But, if each of the crystals in the groups has adequate accuracy, the...

Specifications

SIGNAL INPUT (signal to be gated) Frequency Range dc to 500 kc. Maximum Voltage Level 7 Volts (5 volts, rms). Input Impedance Approximately 10 kilohms. TIMING SIGNAL (signal that controls gate timing) Frequency Range dc to 500 kc. Maximum Voltage Level 10 volts. Minimum Voltage Level 1 volt, peak-to-peak. Input Impedance Approximately 7 kilohms. Triggering Slope selectable, trigger level adjustable from 7 to +7 volts. GATE TIMING Gate-open and -closed intervals can be independently set to 2, 4,...

Spectral Purity

The measuring system shown in Figure 18 wTas also used to obtain spectrum data. The beat frequency between the two oscillators, multiplied 2000 times, is analyzed with a Type 1900-A Wave Analyzer, set for 10-cycle bandwidth, and recorded with a Type 1521 Graphic Level Recorder. The exceptional dynamic range of this combination makes it possible to present the spectrum in a particularly useful form. The oscillators are adjusted to have a beat frequency of about 3 kc (3000 X 10 10). Figure 21 is...

Spectrum

Spectral purity is particularly important for microwave-speetroscopy and for other applications requiring high multiplication ratios. The spectrum of an oscillator provides information beyond that given by long-term and short-term stabilities. It shows the presence of discrete sidebands and the distribution of noise. To compare the spectra of two oscillators, it is necessary to know the frequency and the analyzer band-width. Figure 7 shows a typical spectrum, which is obtained by the Figure 7....

Stability Specifications

No accepted standards exist for the specification of short-term stability. These data are obtained for constant operating conditions, i.e., constant ambient, load, line, etc., and the effects of variations in these quantities are listed separately. The method most suitable for the evaluation of the oscillator performance in systems applications is to specify the standard deviation, a, for a specified confidence limit. This is, of course, the same as the rms deviation. Sometimes rms phase...

Stage

Typical block diagram for a precision oscillator. Figure 6. Typical block diagram for a precision oscillator. Obviously, the best solution would be to ensure that E is small enough to be negligible. This is quite difficult, because even when En is very small, it still has considerable effect. For example, if as low as 1 X 10-5 requires well over 100 db of isolation and shielding between output stage and oscillator, and En is often larger. So far, it has been shown only that the...

Standards For A Soundlevel Meter

The American1 and International2 standards on sound-level meters are written to ensure that measurements made with sound-level meters of various makes and models will be accurate and will agree closely with one another. The American standard specifies seven basic characteristics for a sound-level meter (the International standard is similar). These involve weighting, directionality, crest-factor capacity, attenuator accuracy, detector characteristic, dynamic characteristic of the meter, and...

Stepdown Transformer

Type f 308-a audio oscillator and power amplifier meter cutoff frequency of approximately 0.9 cps. Tone-burst testing allows the average signal power to be kept arbitrarily low, although the pulse, or burst, power level may be very high. This low-duty ratio condition may be necessary if the device under test has nonlinearities (i.e., the test properties depend on power level) and if the test equipment cannot operate continuously at the desired signal or power levels. The General Radio Type...

The Synthesizing Principle Used In Gr Synthesizers

Each DI-1 module in the synthesizer receives an input signal at about 5 Mc s, modifies the frequency of this signal very slightly in two steps, and delivers the modified frequency (again near 5 Mc s) as an input to the next DI-1 unit in the train. Figure 6 is an elementary diagram showing the essential processes performed in a DI-1 unit. In f igure 6 each signal (input and output) is shown as having a frequency that, for convenience, may be regarded as the sum of two components. The first...

The Type B Microwave Oscillator

An improved model of the popular Type 1360 Microwave Oscillator is now in production. Amplitude and frequency stabilities of the carrier under square-wave-modulated conditions have been markedly improved by a diode clamp circuit in the klystron repeller modulator. In addition, regulation of the supply voltage for the 1-kc square-wave generator has stabilized the modulation frequency. These improvements are particularly valuable to those customers who will use the oscillator with the Type 1640-A...

The Unit Pulse Generator

One of our most popular Unit Instruments has long been the Type 1217 Unit Pulse Generator. The reason for its popularity is easy to see It has consistently offered more prf range, pulse duration, and pulse amplitude per dollar than any other instrument of its type. Now, with the introduction of the Type 1217-C Unit Pulse Generator, specifications have been again improved significantly. The size remains the same, and the performance per dollar has again been sharply boosted, to a point where the...

Tracking Generator

In one mode of operation the local-oscillator voltage is heterodyned with a 100-kc crystal-oscillator voltage to produce a beat signal whose frequency is always the same as that to which the analyzer is tuned. As the local oscillator is tuned from 100 to 154 kc, the frequency of the beat signal varies from zero to 54 kc. This beat signal is amplified to provide a maximum of at least 2 volts across 600 ohms. This output can be used to drive a network, amplifier, tape recorder, impedance bridge,...

Tunable Filter

The analyzer also functions as a tunable, selective filter and amplifier. This type of operation is achieved by a second heterodyne operation in which the amplified and filtered signal at 100 kc is beat with the local oscillator to restore the filtered component to its original frequency. The tunable filter has the excellent selectivity characteristics of the particular bandwidth chosen, and the output amplitude is proportional to the component amplitude. The applications for this mode of...

Type A

Continuously variable, 2.5 cps to 25 kc in four decade ranges J -octave and o-octave band pass. Can be driven by Type 1521 Graphic Level Recorder for automatic recording of sound and vibration spectra. See Experimenter, September October, 1963. Direct-reading to 2,000,000 megohms at a test voltage of 500 volts and to 200,000 megohms at 100 volts. For rapid measurements of resistors and insulation resistance. See Experimenter, July, 1963. . . . and see these recently announced products...

Type A Automatic Capacitance Bridge Assembly

The automatic bridge, up until now, either has not been a true bridge at all or has been a monster system with a five-digit price. GR, whose experience with impedance bridges goes back nearly a half-century, has now produced an instrument-sized, instrument-priced, automatic capacitance bridge that is sure to be the standard for such instruments for many years to come. The Automatic Capacitance Bridge Assembly requires only connection of the unknown. The bridge selects the proper range, achieves...

Type A Digital Syncronometer

The standard clock face of the Syncronometer time comparator has gone the way of bridge balance controls, as you can see from the picture of our new Type 1123-A Digital Syncronometer. Hours, minutes, and seconds appear on an in-line Numerik digital readout. The readout, however, is only one of many significant differences between this Syncronometer and its predecessors. The Syncronometer is a time-indicating instrument normally operated by a 100-kc input signal from a precision frequency...

Type A Megohm Bridge

This new megohm bridge, which replaces the venerable Type 544, has many new features that will recommend it to those who measure high resistance, insulation resistance, volume resistivity, and capacitor leakage Ten decade ranges to measure resistance values from 1000 ohms to 1000 teraohms (I03 to 1015 ohms). dial with d 5 range for measurement of small differences to 0.1 can be used for matching resistors and for voltage-coefficient measurements. Self-checking circuits allow quick...

Type A Recording Wave Analyzer

Type 1900-A Wave Analyzer Type 1521 Graphic Level Recorder Type 1521-PIOB Drive Unit Type 1900-PI Link Unit 10 Rolls Type 1521-9464 Chart Paper 10 Rolls Type 1521-9465 Chart Paper Type 1521-P3 80-db Potentiometer* Both bench and rack models are available. The bench model is shipped completely assembled. The rack model is supplied with supports for installation in a standard 19-inch rack. * A 40-ilb potentiometer is installed in the recorder. The 80-db unit is supplied in addition.

Type B Standardfrequency Oscillator

This new crystal oscillator combines high stability with the physical rugged-ncss necessary to withstand vibration and shock, it uses a 5-Mr, 5th-overtone crystal in an all-solid-state circuit of silicon transistors. Both crystal and circuit are held at constant temperature by a proportionally controlled oven. Fiberglas-epoxy etched circuits, cased transformers, and Mil grade electrolytic capacitors make the unit acceptable for many military and government applications. Sine-wave output is...

Type C

Oscillograms showing improvements in pulse symmetry and rise times in Type 1217-C over its predecessor. tude of the 40-mA output pulse is also adjustable, up to 40 volts, peak (the amplitude control is actually calibrated in output impedance). Positive and negative prepulses and a delayed synchronizing pulse are also provided. The circuit is basically that described in an earlier article on the Type 1217-B1 a block diagram is shown in Figure 3. A major design objective was economy,...

Type Decade Resistor

Dimensions Width inches (110 mm), height 4 inches (120 mm) length, 15 inches (400 mm) for Type 1432-Y and 18M inches (470 mm) for Type 1432-Z, Net Weight Type 1432-Y 6 pounds, 5 ounces (2.9 kg) Type 1432-Z 7 pounds, 8 ounces (3.4 kg). Shipping Weight Type 1432-Y 7 pounds (3.2 kg) Type 1432-Z 9 pounds (4.1 kg). Shipping Weight Type 1432-Y 7 pounds (3.2 kg) Type 1432-Z 9 pounds (4.1 kg).

Type Iib Unit Pulse Generator

1,4 0.5 0.6 0.7 o.a os 1.0 i.i time in seconds Figure 6a (below), Test system for measuring deflection vs time for an ac meter. Figure 6b (right). Deflection as a function of time for an ac meter excited by a tone burst. Distortion measurements can be made with tone-burst excitation of speakers.67 A gated microphone is used to respond to the signal produced by the speaker after the tone burst has been cut off. This hangover is a measure of the distortion of the speaker. Such systems are capable...

Uses

A sound-level meter is the basic sound-measuring instrument. Almost any noise study begins with elementary sound-level measurements to determine what further investigation will be needed. Industrial and governmental test codes specify test limits and procedures for making sound-level measurements. The A-weighted sound level is becoming increasingly popular as a measure of the disturbing effect of noise on people. Young3 has recently shown that subjective ratings of office noise are as well...

Volts

Is available as the Type 1910-A Recording Wave Analyzer. The 80 db or more of dynamic range in the filtered output is obtained for signals of 0.3 volt or higher. The term dynamic range is used here to signify the linear range from maximum output to the noise level without readjustment of the controls. This range in many other instruments is significantly less than the analysis range one obtains by resetting the attenuator that controls the meter reading. In this analyzer the two are similar,...

Volume Number

Megohm Wire-Wound Resii Measuring Microinches Transistor Measurements at High Frequencies The General Radio EXPERIMENTER is mailed without charge each month to engineers, scientists, technicians, and others interested in electronic techniques in measurement. When sending requests for subscriptions and address-change notices, please supply the following information name, company address, type of business company is engaged in, and title or position of individual.

Writing Speed And Lowfrequency Cutoff

Low-Frequency Cutoff c s Hespouse down 1 dli) Low-Frequency Cutoff c s Hespouse down 1 dli) Figure 3. Lo w-frequ ency response of the Graphic Level Recorder to ' j-oclave band of pink noise, with a writing speed of 1 in sec. Figure 3. Lo w-frequ ency response of the Graphic Level Recorder to ' j-oclave band of pink noise, with a writing speed of 1 in sec.

From Turnon

Warmup effects on pulse duration. Figure 6. Schematic diagram of the input circuits. Switching at only three points converts a conventional Schmitt circuit, used with external drive, into a wide-range oscillator for internal prf control. trigger spike to output pulse circuit Figure 6. Schematic diagram of the input circuits. Switching at only three points converts a conventional Schmitt circuit, used with external drive, into a wide-range oscillator for internal prf control. trigger...

And Electronics Engineering

Original papers covering the forefront of the art are sought for the First National Conference on Automotive Electrical and Electronics Engineering to be held September 22 and 23 in Detroit, at the McGregor Memorial Center of Wayne State University. Within the context of automobiles and traffic, the following subject categories will be considered 1. Systems and Automatic Control 2. Communication and Signalling 3. Vehicle Propulsion and Control 4. Energy Storage and Conversion 8. Manufacturing...

New Gro Representative For Greece

We announce the appointment of the Greek firm of Marios Dalleggio as exclusive General Radio Company (Overseas) representative for Greece, succeeding the firm of K. Karayannis, who have represented us in that country for many years. Effective January 1, 1964, Marios Dalleggio took over these responsibilities and is now directly serving our customers in Greece with competent technical assistance and advice. All inquiries, whether technical or commercial, concerning General Radio products, should...