Bandwidth and speed of build-up as performance criteria for pulse and television amplifiers

A comparison is made of the two main methods of describing the performance of pulse and television amplifiers, namely bandwidth, and speed of build-up of a suddenly-applied signal. It is shown for a variety of circuit arrangements (including asymmetrical circuits) that equal speeds of build-up based on the slope of the build-up curve at half the steady-state amplitude correspond fairly closely to equal bandwidths measured between the points at which the response is 3 db below that at the applied frequency. It is therefore concluded that either of these criteria would be satisfactory in practice, since they are mutually consistent. Other methods of defining the speed of build-up are discussed, and the main inconsistency is shown to be that, for only one or two stages, but not for larger numbers, the use of the maximum slope of the build-up curve gives misleading results. The problems of humps in the attenuation/frequency response and overshoot in the transient response are only briefly discussed, owing to the difficulty of assessing quantitatively their importance as performance criteria. A few other design factors, especially adjacent-channel interference suppression, are briefly considered in relation to the main discussion.