| 摘要 |
PURPOSE:To deliver simultaneously both the Japanese language and a foreign language to the left and right output lines, by using a simple constitution containing the primary and secondary sound signal demodulating circuits, a matrix circuit and a switching circuit. CONSTITUTION:When a switch S is switched during the receptrion of the sound multiplex broadcase, an FM wave detecting output is supplied to a primary/secondary sound signal demodulating circuit 2. A primary sound signal (L+R) is extracted out of the signal of the circuit 2 via a primary sound signal demodulating circuit consisting of a de-emphasizing circuit 8 and an LPF9 and then delivered to a matrix circuit 3. On the other hand, a secondary sound signal (L-R) is extracted out of the signal supplied to a secondary sound signal demodulating circuit through a BPF14 and undergoes an FM wave detection through an FM demodulating circuit 11. This signal (L-R) is applied to the circuit 3 after the subcarrier of the signal is excluded. A primary sound signal (Japanese) is delivered to fixed terminals P2 and P4 of a switch S4 as well as a fixed terminal P2 of a switch S5 when two sounds are received in the sound multiplex broadcast. While a secondary sound signal (foreign language) is delivered to a fixed terminal P3 of the S4 as well as to fixed terminals P3 and P4 of the S5 respectively. |
