Telecommunications – Receiver or analog modulated signal frequency converter – Signal selection based on frequency
Patent
1981-08-06
1983-08-09
Pellinen, A. D.
Telecommunications
Receiver or analog modulated signal frequency converter
Signal selection based on frequency
455194, H04H 500
Patent
active
043980600
ABSTRACT:
Signal transmitting operation is effected in a muting circuit when a first constant current source connected to the emitters of first and second transistors is operative with a second constant current source connected to the emitters of third and fourth transistors being inoperative. The signal transmitting operation is not effected in the opposite case. A bias resistor is interposed between the bases of the first and third transistors. To eliminate the popping noise when the power source is turned on, a switching element is connected parallel to the bias resistor and is kept in the ON state for a predetermined period of time after making of the power source.
In an FM radio receiver, the output signal of a detuning detection circuit is applied to the input terminals of first and second mute control circuits, and the muting operation of a pre-amplifier for amplifying a stereo composite signal is controlling by the first mute control circuit while the muting operation of a muting circuit connected to the output of a stereo demodulation circuit is controlled by the second mute control circuit. Discrimination levels of these first and second mute control circuits are set to mutually different levels to eliminate occurrence of the popping noise at the time of changes from tuning to detuning and vice versa.
REFERENCES:
patent: 3790714 (1974-02-01), Ohsawa
patent: 3919482 (1975-11-01), Hamada
patent: 4029906 (1977-06-01), Takahashi
patent: 4049918 (1977-09-01), Ohsawa
patent: 4112385 (1978-09-01), Kusumi
patent: 4132953 (1979-01-01), Martin
patent: 4143331 (1979-03-01), Page
patent: 4157455 (1979-06-01), Okatani et al.
patent: 4191851 (1980-03-01), Honma et al.
patent: 4244056 (1981-01-01), Hamada et al.
Ienaka Masanori
Iso Yoshimi
Hitachi , Ltd.
Pellinen A. D.
LandOfFree
Muting circuit for an FM radio receiver does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Muting circuit for an FM radio receiver, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Muting circuit for an FM radio receiver will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-588553