## Oscillators For Superheterodyne Reception

Introduction.1 Any reversible system which is capable of storing and releasing energy, i.e., changing its form from potential to kinetic and back again, can be made to oscillate. If the release and storage can be achieved without loss of energy the system will continue to oscillate when once set in motion. This condition cannot be realized in practice because energy is always dissipated when any interchange takes place, and the oscillation amplitude decays according to an exponential law...

## Info

The most suitable values of gl and fs2 are those giving the minimum error variation over the wave range, and to determine them the error curve shape must be known. The best choice is Fig. 6.16. The Ideal Curve for Two-point Zero Error Ganging. Fig. 6.16. The Ideal Curve for Two-point Zero Error Ganging. clearly either that which gives errors equal in magnitude at the ends and centre of the range, or least error at the low frequency end of the range where the signal circuits are normally more...

## Fgw

Most coil, screens for mechanical rigidity require to be made of at least 20 S.W.G., which gives a thickness of 0 036 inch, a value greater than that required for electrical screening at this low frequency. At higher frequencies the required thickness decreases. Bogle also gives the following formula for the ratio of the change in inductance to the screened inductance due to eccentricity of the axes of the coil and screen. where e the eccentricity of the axes. Let us suppose the coil in the...

## Bibliography

Frequency Variations in Thermionic Generators. K. E. Edgeworth Journal I.E.E., Vol. 64, 1926, p. 349. 2. On the Variation of Generated Frequency of a Triode Oscillator. K. B. Eller, Proc. I.R.E., Dec. 1928, p. 1,706. 3. Constant Frequency Oscillators. F. B. Llewellyn, Proc. I.R.E., Dec. 4. A Recent Development in Vacuum Tube Oscillator Circuits. J. B. Dow. Proc. I.R.E., Dec. 1931, p. 2,095. Correction ibid., Jan. 1932, p. 182, 5. Ganging the Tuning Controls of a Superheterodyne Receiver. A. L....

## Eo mK [igmgM

Usually gm oc Ia and gs a Is so that In non-aligned grid tetrode valves is about 0-25 and in aligned 2.8. The Grid Input Admittance of a Valve.8 2.8.1. Introduction. The grid input circuit of a valve can usually be represented by a resistance and capacitance in parallel. The magnitude of both components depends on the construction of the valve, the potentials applied to the electrodes, and the impedances in the external circuits connected to the electrodes. The input resistance can be due to...

## Wwm

C gt o o a es c gt a 3- si o lt x gt ' 3.5.3. The Aerial to Feeder Connection. We will consider first the case of a feeder correctly terminated at the receiver end in its characteristic impedance Z . Owing to the fact that the aerial input impedance varies over the frequency range and is reactive, except at its resonant frequencies, there must be a loss of power transfer at the j unction of feeder and aerial. The maximum power transfer occurs when the load resistance the characteristic...

## Lvm

Equal to VR2 X2, but its phase angle is lt f gt tan-1 i.e., the reactance term is capacitive. Thus the amplitude is inde pendent of the sign of the real and imaginary terms in the j representation. Only the phase angle is affected. 2. A term containing a complex denominator must be rationalized before the phase angle is determined, for example, a circuit having an impedance Z R jX has an admittance Y - . The amplitude of the admittance Y 1 but its phase angle is not lt j gt tan-1 but d gt tan-1...

## Msx

From curve 3, Fig. 8.116, it may be noted that RE for the parabolic diode is higher for small values of tlx, but for large values of there is little difference between it and the linear diode. The detection efficiency is less in the parabolic case curve 3 in Fig. 8 11a , except for very small signal voltages, when it is superior to the hnear diode curve 1 because, due to curvature of the characteristic, there is always some detection For the linear diode

## Pye Short Wave Radios Converters

A New System of Short Wave Amplification. E. H. Armstrong, Proc. 2. The Superheterodyne, Its Origin, Development and Some Recent Improvements. E. H. Armstrong, Proc. I.R.E., Oct. 1924, p. 539. 3. On the Origin of the Superheterodyne Method. W. Schottky, Proc. 4. Recent Developments in Superheterodyne Reception. G. L. Beers and W. L. Carlson, Proc. I.R.E., March 1929, p. 501. 5. Considerations in Superheterodyne Design. E. G. Watts, Proc. I.R.E., 6. Undesired Responses 'in Superheterodynes....

## Franklin Oscillator Valve Lc

From the above it would appear possible to neutralize the frequency variation due to by inserting a suitable correcting reactance in series with the grid or anode lead. An improvement in frequency stability can be brought about by the inclusion of a neutralizing reactance but, since the latter must be varied when the LC circuit frequency is varied, it is not feasible for correcting oscillators covering a large frequency range. Furthermore, owing to non linear operation of the valve, reactance...

## Q

Thus a and 1 can also be defined in terms of the frequency Expressions 6.45c, 466 and 476 are plotted in Fig. 6.21 against i- for IsL. 1-091, Is . 1-82, J - 2-545, which means that for the medium wave range and fmin 550 kc s, fsl 600 kc s, fs2 1,000 kc s, fs3 1,400 kc s. These were the original zero error frequencies chosen by the authors of this method. From the curves in Fig. 6.21, the component ratios for an i.f. of and if the maxim am value of the total tuning capacitance is 536-8 fijuF,...