Apparatus for monitoring pulses

Claim 1

Apparatus for producing an output signal generally proportional to the log of the average rate of random pulses, which rate varies over a total pulse rate range which extends substantially below and above the range of 104 to 106 pulses per second, comprising means employing a pulse counting technique for producing a first intermediate signal proportional to the log of the average pulse rate of the random pulses in a predetermined lower portion of the total pulse rate range, a Campbelling circuit for producing a second intermediate signal proportional to the log of the average pulse rate of the random pulses in a predetermined upper portion of the total pulse-rate range, said upper portion and said lower portion having an overlapping region in the total pulse-rate range, said first and second intermediate signals having the same proportional relation to the log of the average pulse rate, means for applying said first and second intermediate signals to an output point, means for limiting said first intermediate signal at a selected level for averaGe pulse rates above a predetermined rate in the overlapping region, and means for cutting off said second intermediate signal for average pulse rates below said predetermined rate, thereby providing a continuous output voltage at the output point that is proportional to the log of the average pulse rate over the entire range.