Abstract: A logarithmic amplifier calibrator having a signal generator providing an exponentially decaying calibration signal and a pulse generator providing a sample pulse each time the calibration signal has decayed by a predetermined decibel (db) increment. More specifically, the calibrator includes a crystal which is excited to an energy level through a feedback loop having an amplification means whose gain is controlled by a voltage controlled attenuator. The decay characteristics of the crystal when installed in the calibrator are determined so that the time required for the crystal to decay over an entire calibration range is known. This time is then divided into a plurality of time increments, each time increment corresponding to a predetermined db drop in the calibration signal. Sample pulses derived from a high frequency, high stability oscillator in the calibrator are developed to correspond to each of the predetermined time increments.

Abstract: A system for synchronizing a clock signal generated by a lower stability clock generator to a received incoming signal whereby a higher stability clock generator is synchronized to the lower stability clock generator when the clock signal is synchronized to the incoming signal, and the lower stability clock generator is synchronized to the higher stability clock generator when the incoming signal is lost. More specifically, in a spread spectrum receiver for receiving a signal phase modulated by a pseudo-random code, a means for synchronizing a receiver pseudo-random code generator to the incoming code modulation is provided. The code generator is clocked by a relatively low stability voltage controlled crystal oscillator (VCXO) whose output frequency is controlled by an error signal created by a phase difference between the received code modulation and the output of the pseudo-random code generator.