Damping Measurements of Resonance Bars

Researchers at Notre Dame University have approached the study of material damping capacity from the beginning, rather than the end. One of the most common procedures for measuring the internal friction of material is the resonance-bar technique, wherein a sample of the material to be studied is cut to the proper dimensions for resonance at some desired frequency in some specific mode of vibration. Damping is determined either with the specimen at resonance or in free decay from resonance. Dr....

Magnitude Channel

Figure 1, Block diagram of GR 1654 I mpedance Comparator. Comparison precision to 30 parts per million. Impedance range from 2 2 to 20 Mii at 100 Hz. Capacitance range as low as 0.1 pF direct reading, with a modified substitution method.* Six deviation ranges from 0.1 to 30 full scale. Test voltages from 0.3 to 3 volts, for easy voltage-coefficient tests. Operating rate up to 4 units per second, in the automatic test mode. Positive indication of direction of overload. Indications on large panel...

Typical Applications

The GR 1641 Reflectometer has wide application in production-test facilities development, research, and calibration laboratories incoming inspection and quality-control activities. It measures one-port, two-port and multiport devices, both passive and active, with bidirectional or unidirectional properties. With GR900 precision coaxial adaptors, accurate measurements can be made on devices equipped with a wide variety of connectors. Information can be obtained on a fixed- or swept-frequency...

Standardsignal Generator Improves Its Versatility

Most standard-signal generators do not provide adequate sweep capabilities. On the other hand, sweep-signal generators lack both short- and long-term stability in the cw mode and are therefore of little value in critical point-by-point tests. To meet the increasingly stringent requirements for both sweep and point-by-point testing of high-frequency networks up to 80 MHz, General Radio has made available several new models of the well-established GR 1003 Standard-Signal Generator.1 Redesign of...

The Counter Punch

Diminutive in size and cost, the GR 1192 Counters successfully match their bigger brothers in versatility, sensitivity, and immunity from noise. These instruments can interface with computers they count up to 500 MHz (using the GR 1157-B Scaler) and offer precisions of 5,6, or 7 digits. The digital electronic counter is today a widely accepted, basic measuring tool used side by side with the oscilloscope, voltmeter, and signal source. It is also the youngest member of that family of tools...

O

' rouiwo fthiae on um inimvai miio count ' rouiwo fthiae on um inimvai miio count Combination of GR 1157 Scaler and GR 1192 Counter assembled for rack mounting. Combination of GR 1157 Scaler and GR 1192 Counter assembled for rack mounting. The GR 1157-B Scaler, compatible with the GR 1191- and 1192-series Counters, replaces the popular GR 1157-A Scaler. This model includes improvements such as Greater counter resolution at frequencies that only require prescaling by 10, by the addition of a...

SWR

Detailed expansion of 3.75-GHz resonance in Figure 24 full scale 1.35 SWR and 10 dB loss . Figure 26. SWR curves for assorted adaptor pairs and cables in the 250- to 500-MHz range full scale 1.03. Curve A shows the response with 900-W50 Termination connected at UNKNOWN port of rf unit, curve B the response with a pair of 900-Q874 Adaptors inserted between termination and UNKNOWN port. Curve C indicates response after substitution of 900-QN Adaptors for 900-Q874 Adaptors, curve 0...

Vm

Schematic diagram of high-frequency unit. Figure 4a. Schematic diagram of low-frequency rf unit. Figure 6. Typical calibration curves for SWR measurements in 2.0- to 4.0-GHz range full scale o. Figure 6. Typical calibration curves for SWR measurements in 2.0- to 4.0-GHz range full scale o. Figure 7. SWR measurement of 1.5 1 mismatch in the 2.0- to 4.0-GHz range full scale 2.0. Figure 7. SWR measurement of 1.5 1 mismatch in the 2.0- to 4.0-GHz range full scale 2.0. Figure 8. SWR...

Stable Series Of Coaxial Resistance Standards

The GR 1442 Coaxial Resistance Standards Figure 1 are the most recent addition to the line of General Radio impedance standards with coaxial connectors. As in the capacitors described previously,1,2 the GR900 connectors make it possible to have two-terminal impedance standards for the radio-frequency range, which can be calibrated to a high degree of accuracy. The GR 1442 resistor consists of two GR900 connectors with a short length of outer conductor forming the housing for the resistor. The...

Closer Look At The Detector

A unique design deserves some elaboration in order to stress its qualities and advantages. This section expands upon our previous presentation of design details and refers to Figure 8. The Multiplexer is an electronic switch with up to 45 inputs and one output. The input channels are switched on in sequence by command from the system control, using addresses coded in an 8 X 6 matrix. Three extra input channels are available one is left unused, the other two are reserved for calibration...

Internal Clock Oscillator

Frequency Control 10-MHz third-overtone quartz crystal in proportional-control oven. Temperature lt 1 ppm, 0 C to 50 C. Warmup Within 1 ppm from room temperature in 10 min. Short-Term Stability 1 X 10 7 for 1-s sampling interval. Long-Term Stability 1 X 10 6 per year with oscillator running continuously, lt C 3 X 10' per day after one month of operation. Internal Clock Output 1 V rms into 50 ii. Output Pulse 5 V behind 50 n positive and negative available simultaneously. Duration approx 15 ns...

Rumi

Block diagram of GR 1662 Bridge. drive DVM's, limit comparators, dc recorders. HI-GO-LO limit indication by panel lights. Manually-preset or external-pro-grammable limiting. Less than 12 mW dissipated in unknown minimizes self-heating effect on low-power devices . The block diagram of the GR 1662 bridge, Figure 1, shows the basic elements of the instrument a dc generator, an active Kelvin bridge, a detector amplifier, and the HI, GO, LO limit circuitry. The floating dc generator is...

Unbalance Amplifier

Leong holds degrees from North astern University BSEE-1960 and MSEE-1962 . After two years' service in the U. S. Army as 1s Lt., coordinating instrumentation for upper atmosphere research, he joined GR in 1964 as a development engineer in the Low-Frequency Impedance Group. He has specialized in bridge and comparator design. He is a member of Tau Beta Pi and Eta Kappa Nu. ence between the test item and the standard. The 1782 accessory unit Figure 2 incorporates front-panel lamps to...