Abstract: An RF carrier signal is frequency modulated by a modulating signal, as a function of the amplitude of the modulating signal. The number of cycles in the frequency modulated carrier is counted in a first counter during the positive half cycle of the modulating signal and in a second counter during the negative half cycle of the modulating signal. A microprocessor obtains the difference of the counts in the counters, and from the difference computes the deviation of the modulated carrier from the center frequency of the carrier. This is compared with a desired deviation and the microprocessor calculates and generates a correction signal to vary the amplitude of the modulating signal when the difference between the computed and desired deviation exceeds a predetermined value. An arrangement is also provided whereby, after a calibration procedure, an external source may provide the modulation signal.

Abstract: A frequency detection circuit is disclosed that employs a phase lock loop circuit in operative cooperation with a microprocessor. The microprocessor provides a control signal to an oscillator of the phase lock loop circuit so as to control its free-running frequency. The microprocessor has prestored quantities that represents predetermined parameters for measuring the frequency components contained in a tone burst transmitted from a sonobuoy. The microprocessor provides an output signal if the measured parameters correspond to predetermined and desired parameters. The microprocessor has predetermined parameters for measuring the length of the tone burst. The microprocessor provides a serial output signal transmitting the frequency and tone burst length measurements.

Abstract: An RF carrier signal is frequency modulated by a modulating signal, as a function of the amplitude of the modulating signal. The number of cycles in the frequency modulated carrier is counted in a first counter during the positive half cycle of the modulating signal and in a second counter during the negative half cycle of the modulating signal. A microprocessor obtains the difference of the counts in the counters, and from the difference computes the deviation of the modulated carrier from the center frequency of the carrier. This is compared with a desired deviation and the microprocessor calculates and generates a correction signal to vary the amplitude of the modulating signal when the difference between the computed and desired deviation exceeds a predetermined value. An arrangement is also provided whereby, after a calibration procedure, an external source may provide the modulation signal.

Abstract: A frequency detection circuit is disclosed that employs a phase lock loop circuit in operative cooperation with a microprocessor. The microprocessor provides a control signal to an oscillator of the phase lock loop circuit so as to control its free-running frequency. The microprocessor has prestored quantities that represents predetermined parameters for measuring the frequency components contained in a tone burst transmitted from a sonobuoy. The microprocessor provides an output signal if the measured parameters correspond to predetermined and desired parameters. The microprocessor has predetermined parameters for measuring the length of the tone burst. The microprocessor provides a serial output signal transmitting the frequency and tone burst length measurements.

Abstract: A system, and a method of operation thereof, for analyzing the performance f a tape recorder having a playback head is disclosed. The system allows for the recorded data of the tape recorder to be routed to a analog-to-digital converter whose output is delivered to a digital signal processor preferably having a routine to convert the digital data to an FFT data stream which, in turn, is routed to a microprocessor. The computer analyzes the FFT data and provides digital signals to external display devices that indicate the proper recording of the tape recorder, the need for the recorder's heads to be cleaned, the occurrence of excessive dropout data recording rate, or the need to manually or automatically adjust the bias and equalization levels of the tape recorder.

Abstract: A system for verifying the operational performance of command tone generas, transmitters, and antennas including its signal quality and strength as well as its reflected power is disclosed. The system includes a receiver that receives a RF signal and develops an output AM demodulated signal having a d.c. component that is proportional to the amplitude of the received RF signal. The d.c. component serves as an AGC input for the receiver so as to hold the AM demodulated signal constant within a specified range for the input RF signal. The AGC value is digitized to form tuned RF power in sync with the address detection with a microprocessor correcting for AGC nonlinearities.

Abstract: A calibrated VHF/FM source for use in correcting tape recorder and receiver rrors which consolidates these functions in a lightweight rack using commercial test parts and maintains a high precision of accuracy by having the system monitor it's own output and correct the distortion and amplitude errors attributable to the nonlinear behavior of the a Voltage Variable Capacitance diode (VVC diode) of the Voltage Capactive Oscillator (VCO) of the VHF FM transmitter.

Abstract: A system, and a method of operation thereof, for analyzing the performance of a tape recorder having a playback head is disclosed. The system allows for the recorded data of the tape recorder to be routed to a analog-to-digital converter whose output is delivered to a digital signal processor preferably having a routine to convert the digital data to an FFT data stream which, in turn, is routed to a microprocessor. The computer analyzes the FFT data and provides digital signals to external display devices that indicate the proper recording of the tape recorder, the need for the recorder's heads to be cleaned, the occurrence of excessive dropout data recording rate, or the need to manually or automatically adjust the bias and equalization levels of the tape recorder.