Complex analog waveform generator

DETAILED DESCRIPTION In FIG.
1, a signal generator 10 is connected via a transmission channel 21 to a signal receiver 22.
Signal generator 10 comprises a clock 11 connected to a divider chain 12 which produces a 9-bit signal for a signal memory 13.
Additional information concerning divider chain 12 will be discussed hereinafter in connection with FIG.
2.
The 9-bit signal addresses signal memory 13 to gain access to code words contained therein which are indicative of quantized samples of the analog signal being generated.
These code words are applied to converter 14 which comprises gating network 16 and D/A (digital-to-analog) decoder 17.
Converter 14 produces an analog step signal which is a quantized version of the analog signal being generated.
Lowpass filter 18 receives the quantized version of the analog signal and serves to remove the step effect or sharp transitions from the output of converter 14.
The smoothed output of filter 18 is applied to attenuator 19 which serves to adjust the amplitude of the analog signal for transmission through channel 21.
For the sake of convenience, the signal from filter 18, which is applied to channel 21, will be referred to as the line signal.
The line signal after transmission is applied to receiver 22 wherein the signal passes through serially connected AGC (automatic gain control) circuit 23 and bandpass filter 24 to ratio circuit 26.
AGC circuit 23 receives a full-wave rectified average version of the signal applied to ratio circuit 26.
AGC circuit 23 adjusts its gain so that the amplitude of the signal from ratio circuit 26 corresponds to a predetermined value.
Filter 24 shapes the spectral response of receiver 22 and serves to reject out-of-band signals from application to ratio circuit 26.
Ratio circuit 26 performs a ratio measurement to provide a digital indication of P/AR (peak-to-average ratio) which is computed by ##EQU1## where E (peak) = normalized peak value of the envelope of the analog pulse signal.
E (fwa) = normalized full-wave rectified average value of the envelope of the analog pulse signal