| 摘要 |
PURPOSE:To give the good stereo decoding signal to the demodulator, by giving specific signal to the multiplication signal given to the phase comparator to avoid the production of great sprious interference in the output signal of the comparator. CONSTITUTION:The stereo decoding signal generation circuit PSS consists of the PLL circuit such as the oscillator VCO possible for control, phase comparator PC, LPF, frequency dividers Div1, Div2 and the gate circuit GC. The signal forming circuit SC giving the oscillation waves from the oscillator VCO outputs the asymmetrical rectangular waves S1 or -S1 having the fundamental frequency twice that of stereo composite signal, duty ratio of 2/3 and the first specified phase. The signal S1 or -S1 is given to the circuit GC, frequency divider Div1 and stereo demodulator FD. The frequency divider Div1 gives the output of S2 or -S2 having equal fundamental frequency as the decoding signal and duty ratio of 50% to the demodulator FD, circuit GC and frequency divider Div2 and the output of circuit GC and frequency divider Div2 is given to the comparator PC. |
