| 摘要 |
<p>1536961 Stereophonic receivers SIEMENS AG 18 Feb 1976 [13 March 1975] 06290/76 Heading H4R In a frequency modulated stereophonic signal receiver the multiplex signal is fed to the decoder circuit via a differential amplifier 5 having a feedback circuit including an RC circuit R K , C K which provides compensation for the frequency and phase response of the connection line between the demodulator and decoder, which forms effectively a low pass filter R A C A . The arrangement reduces cross-talk which can be produced if the amplitude and phase of the L+R and L-R signals are not correct. As described, the multiplex input signal MPX is applied to a differential amplifier 18, 19, having a current mirror circuit in its collector circuits. The output from transistor 18 is fed via amplifier transistor 25 to the output terminal 8 and also via RC circuit 9, 10, as negative feedback to the base of transistor 19 of the differential amplifier. The RC circuit 9, 10, provides the frequency characteristic compensation while the resistor 11 prevents the gain of the circuit becoming too high at high frequencies, i.e. above the stereo signal band. The circuit can be produced in integrated form.</p> |
