NOISE REDUCING CIRCUIT FOR AUDIO SIGNAL REPRODUCING DEVICE

• Main Author: NAKAGAWARA KENJI
• Format: Patent
• Language: English
• Published: 10.08.1988
• Subjects: INFORMATION STORAGE; INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORDCARRIER AND TRANSDUCER; PHYSICS

PURPOSE:To reduce the noise due to the variation of frequency in a reproduced FM audio signal at the time of head switching by adjusting the correction signal level in accordance with physical contraction (skew or the like) of a recording medium like a magnetic tape. CONSTITUTION:A head switching signal is delayed in a delay circuit 17 by a time corresponding to the time delay of the reproduced FM audio signal from the output terminal of a switching circuit 7, which switches reproduced FM audio signals from rotary heads 2 and 3 to obtain the continuous reproduced FM audio signal, to the input terminal of a demodulating circuit, and this delay signal is differentiated by a differentiation circuit 19 to generate a correction signal. The correction signal has the level adjusted by a level adjuster 20 and is supplied to the demodulating circuit with the phase opposite to that of the noise due to the variance of frequency of the reproduced FM audio signal at the time of head switching. The frequency variance component of the reproduced FM audio signal is supplied synchronously with the head switching signal and the time delay behind the head switching signal, and the correction signal is supplied to practically reduce the frequency variation component. Thus, the noise due to the variation of frequency of the reproduced FM audio signal is reduced.