Telecommunications – Receiver or analog modulated signal frequency converter – Squelch
Patent
1985-07-02
1987-01-13
Ng, Jin F.
Telecommunications
Receiver or analog modulated signal frequency converter
Squelch
455225, 455221, 455303, H04B 110
Patent
active
046370668
ABSTRACT:
A noise blanking signal generator for an AM radio receiver includes a product detector adapted to receive an IF signal modulated by an AF signal and synchronously detect the AF signal, a first low pass filter adapted to derive from the product detector a filtered voltage indicating the average IF signal strength, a second low pass filter adapted to derive from the product detector an AF signal voltage and a reference voltage generating circuit ratiometrically related to the product detector through a common DC power supply and effective to generate a reference voltage substantially equal to the filtered voltage in the absence of an IF signal. A voltage divider comprising a pair of resistors connected in series across the outputs of the first and second low pass filters has an output at the junction of the resistors, the resistors being of such ratio as to generate, when the AF signal equals a predetermined modulation level with reference to the IF signal strength, a voltage equal to the reference voltage at the voltage divider output, a comparator effective to compare the voltage at the output of the voltage divider with the reference voltage and generate a noise blanking signal when the former exceeds the latter and offset means effective to bias the comparator do not generate the noise blanking signal when the voltage at the output of the voltage generator does not exceed the reference voltage.
REFERENCES:
patent: 4044309 (1977-08-01), Smith
patent: 4053843 (1977-10-01), Wright et al.
patent: 4300104 (1981-11-01), Tanaka et al.
patent: 4327446 (1982-04-01), Dressler
patent: 4342120 (1982-07-01), Settlemire et al.
Aldridge Fredrick A.
Kennedy Richard A.
General Motors Corporation
Ng Jin F.
Seidenglanz Elissa
Sigler Robert M.
LandOfFree
Noise blanking signal generator for AM radio does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Noise blanking signal generator for AM radio, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Noise blanking signal generator for AM radio will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2361590