195 KC SONAR F M MODULATOR

Description: This device is utilized for recording signals from active sonar onto magnetic tape, allowing for subsequent playback to manage land-based sonar systems used in the training of operators. The modulator functions as a sawtooth generator, with its repetition frequency being altered by the amplitude of the modulating input signal.

The circuit described involves a modulator that plays a crucial role in the recording of sonar signals. The active sonar system emits sound waves and captures their reflections to detect underwater objects. The signals generated are then fed into a modulator, which serves as a sawtooth waveform generator. This generator produces a linear ramp signal that rises and falls, resembling a sawtooth pattern.

The frequency of the sawtooth waveform is not fixed; instead, it is dynamically modulated by the amplitude of the input signal derived from the sonar system. When the amplitude of the input signal increases, the frequency of the sawtooth waveform also increases, allowing for a more rapid succession of recorded sonar pulses. Conversely, a decrease in the input signal amplitude results in a lower frequency of the sawtooth waveform.

The output from the modulator is then recorded onto magnetic tape. This tape serves as a medium for storing the modulated sonar signals, which can later be played back for analysis or training purposes. During playback, the recorded signals are retrieved from the tape and processed to control land-based sonar systems, facilitating the training of operators in interpreting sonar data.

The overall design requires careful consideration of the components involved, including the sawtooth generator, amplifiers, and the magnetic tape mechanism. The modulator’s performance is critical, as it directly influences the fidelity of the recorded signals and, consequently, the effectiveness of the training provided to sonar operators. Proper tuning and calibration of the circuit are essential to ensure accurate signal representation and reliable playback quality.Used in recording signals from active sonar on magnetic tape, for later playback to control land-based sonar used in training operators. Modulator is basically sawtooth generator whose repetition frequency is changed by amplitude of modulating input signal.

-M. H. Damon, Jr. , Tape Target Classifier Trains Sonar Operators, Electronics, 33:13, p 65-6 9.