A Construction of Adaptors Recording and Reproducing the DC Signal by Using Phase Locked Loop IC

The frequency modulator and demodulator of the DC signal were made by using phase locked loop IC. The usual audio tape-recorder connected with the adaptors could record and reproduce the DC signal as like the instrumentation tape-recorder. The drift, distortion ratio, and the linearlity of the output of the recorder were measured. The ratio of the signal to noise (S/N), output noise and the output voltage of the recorer were 55dB, 1mV, and 0.6V r. m. s., respectively. These values were similar to those of the instrumentation tape-recorder.