The response of a linear diode-voltmeter to single and recurrent r.f. impulses of various shapes

Abstract

An analysis is given of the response of a linear diode-voltmeter to r.f. impulses, of the indication of a meter measuring the rectified voltage, and of the damping effect of the diode on the preceding circuit.The response to a short single impulse of arbitrary shape is evaluated in terms of the time-integral or area of its envelope. The ratio of this area to the peak amplitude is termed the effective duration of the impulse.The response to recurrent impulses whose spacing is small compared with the discharge time-constant is expressed in a general manner and graphed for the cases of rectangular and triangular impulses. The “effective charge time-constant” of the voltmeter depends on impulse and circuit parameters. The rectification efficiency for triangular impulses is found to lie between 0.75 and 1 times that for rectangular impulses of the same effective duration and periodicity. It is inferred that for most practical impulses the rectification efficiency will lie between the values shown graphically for triangular and rectangular impulses when expressed in terms of effective duration of the impulse.The maximum indication of a critically damped meter to the rectified voltage produced by the application of a single impulse is evaluated in terms of the ratio of the meter and discharge time-constants.The damping imposed by the diode rectifier on a sharply tuned circuit is calculated for single and recurrent impulses and shown to be considerably greater than for continuous waves.