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7187775 Audio signal recording apparatus  
When a plug of a monaural microphone is connected to an external microphone input section, a right channel terminal is connected to a GND terminal, and a voltage Vdet will be a GND potential. A DC...
7107024 FM modulator output control during turn on  
The present invention provides a system and a method to prevent undesired sounds during FM modulator turn on. The system includes an RF attenuator circuit, a delay switch circuit, an RF ramp up...
6823072 Peak to peak signal detector for audio system  
A peak to peak detector circuit for use in an audio system comprises a first amplifier having an input terminal for receiving an L+R AC audio signal and an output terminal which is serially coupled...
5862189 De-interleaving and buffering in one memory  
In a digital audio broadcast receiver a digital audio transmission signal is supplied to a demodulator which provides demodulation samples. The demodulation samples are de-interleaved in a first...
5737034 Radio frequency modulator having an audio multiplex broadcasting function  
A radio frequency (RF) modulation apparatus for modulating input video and audio signals into a television broadcast signal is provided. The apparatus includes a buffer amplifier, a decoder, a...
5696830 Circuit arrangement for deriving a quality signal dependent on the quality of a received multiplex signal  
The method for obtaining the quality signal includes multiplying a digital multiplex signal (MPX) by respective reference carrier signals mutually phase shifted by 90° to each other, but otherwise...
5682431 FM stereo broadcasting apparatus and method  
The FM stereo broadcasting apparatus has a sampling frequency converter for receiving a digital input signal having an L (left audio)-signal and an R (right audio)-signal and for converting the...
5619577 Transmission system, and a transmitter and a receiver for use in such a system  
A simple and effective stereophonic transmission system (1) wherein the transmitter (2) alternatively encodes successive block periods of a block signal with samples of the left-hand channel signal...
5604808 FM signal processor  
An FM signal phase-shifted by 90° and an FM signal not phase-shifted are supplied to a multiplier to demodulate a stereo composite signal. A 90° phase shifting circuit has a first oscillation...
5590203 Pilot signal detection circuit  
A pilot signal detection circuit comprises: a PLL circuit for generating a reference signal whose frequency is same as and phase-synchronized with a carrier of a pilot signal extracted from...
5442709 Circuit for decoding a multiplex signal in a stereo receiver  
In a circuit for decoding a multiplex signal in a stereo receiver, where the multiplex signal contains a composite signal (L+R) in the base band, a subcarrier modulated with a difference signal...
5416843 Devices, systems and methods for composite signal decoding  
A device and method for composite signal decoding is provided in which an analog to digital converter (18) digitizes an incoming composite signal. The digitized signal is transmitted to a least...
5404405 FM stereo decoder and method using digital signal processing  
A digital FM stereo decoder uses the phase characteristics of linear phase FIR filters, together with a trignometric operation, to generate a 38 kHz subcarrier signal from a 19 kHz pilot. The...
5357544 Devices, systems, and methods for composite signal decoding  
A method is provided for decoding a composite signal which includes receiving a composite signal including a pilot signal at a pilot signal frequency, and first and second information modulated...
5289543 FM receiver and communication systems including same  
An FM receiver includes an FM discriminator having a comparator for converting the FM signal to a series of discrete square-wave pulses all of the same amplitude and of a repetition rate varying...
5282224 Signal processing integrated circuit device  
There are provided a modulation circuit (9) and a signal processing circuit (2) on the same chip. The modulation circuit (9) modulates an input signal (30) to apply it to a selector (8). The...
5257312 Time-discrete stereo decoder  
A receiver having a signal path incorporating a tuner, a demodulator circuit for supplying a stereo multiplex signal having a baseband stereo sum signal (L+R), a 19 kHz stereo pilot and a stereo...
5255319 Noise suppressing circuit in an FM tuner  
A noise suppressing circuit has a gate for controlling a composite signal applied to a stereo demodulator of an FM tuner, and a detector for detecting a noise included in the composite signal and...
5239585 Devices, systems, and methods for composite signal decoding  
Generally, and in one form of the invention, a composite signal decoder (60) is disclosed which does not require synchronizing the sampling rate to the phase of the incoming pilot signal. Curve...
5220607 Digital switching signal in stereo decoders and circuit array for generation thereof  
In stereo receivers with digital decoding pulse generation, interference by the harmonics of the digital switching signal with signals in adjacent channels or with carrier signals in the sideband...
5179593 FM stereo receiving device  
An FM stereo receiving device according to the present invention has an object to be able to demodulate a stereo signal in a state close to a monaural reception, in which a pilot signal is...
5155769 Discrete parallel path modulation multiplexer  
A discrete parallel path modulation multiplexer for use in generating a composite baseband signal from separate left and right input signals. The composite baseband signal includes the sum of the...
5107134 Matrix circuit of FM stereo multiplex demodulation circuit  
A matrix circuit includes a first resistor having one end connected to receive a current signal and another end connected to a first output node, a second resistor having one end connected to the...
5054070 Stereo signal communication system and method  
A system which enables transmission of a standard composite stereo sound signal, made up of baseband, subcarrier band and pilot signals, from a first location to a second location while requiring...
5014316 Compatible quadrature amplitude modulation detector system  
An audio detector circuit forms L+R and L-R audio signals from an intermediate frequency compatible quadrature amplitude modulated signal in the form (1+L+R)cos(fct+φ) where φ contains phase...
4991015 Method and circuit arrangement for identifying the presence or absence of at least one frequency of a known value in an input signal compound of a plurality of frequencies  
A method and circuit arrangement identifies the presence or absence of known frequencies in an input signal composed of a plurality of frequencies, whereby a frequency generator controlled by a...
4982431 Signal distinction circuit  
A signal distinction circuit comprising a noise detector for detecting a noise included in a received signal; and a maintaining circuit for maintaining the condition of a signal outputted from a...
4933974 Switched capacitor pilot phase and magnitude detector  
A switched capacitor low pass filter is used to sample an FM stereo composite signal with non-overlapping clock signal to achieve phase or magnitude detection of the 19 kHz pilot without being...
4932058 Pilot cancellation circuit  
A switched capacitor pilot cancellation circuit included in an FM stereo decoder signal path which substantially eliminates the 19 kHz pilot from the FM composite by subtracting a reconstructed...
4893341 Digital receiver operating at sub-nyquist sampling rate  
A digital receiver samples data from an amplitude modulated subcarrier at a rate less than twice the subcarrier's maximum frequency by sampling at known phase points. Sampling at known phase points...
4870684 PLL circuit for generating output signal synchronized with input signal by switching frequency dividing ratio  
A PLL circuit comprises a variable frequency divider (7) for frequency-dividing a signal having a reference frequency f 1 with a frequency dividing ratio n 1 or n 2 , a fixed frequency divider...
4860354 Arrangement for decoding a stereo multiplex signal  
Arrangement for decoding a stereo multiplex signal, having a baseband stero signal (L+R), a stereo difference signal (L-R) which is amplitude-modulated on a suppressed sub-carrier, and a pilot...
4827515 Digital demodulator  
A digital demodulator demodulates and separates the individual components of a digitized stereo multiplex signal which contains a narrowband information channel at three times the pilot signal...
4817167 Method of receiving frequency-modulated stereo multiplex signals  
A method and a circuit arrangement for receiving frequency-modulated stereo multiplex signals is disclosed in which the channel to be received is converted to the zero IF using negative feedback...
4817150 Oscillator frequency control arrangement for a stereo decoder  
A charge pump arrangement receives a digital error word representing an error signal and charges or discharges a capacitor in accordance with the sign of the error word by an amount that is...
4757538 Separation of L+R from L-R in BTSC system  
A stereo signal separation system for separating the L+R and L-R components of a BTSC stereo signal mixes the BTSC signal with a multiple of the pilot frequency. To recover the L+R component the...
4727580 Radio receiver  
A radio receiver most suitable for use in a car includes a pulse count demodulating circuit and a second demodulating circuit other than a pulse count detecting circuit so that a demodulation...
4723288 Stereo decoding by direct time sampling  
A stereo decoder is provided for decoding an encoded stereo signal. In one form, the encoded stereo signal is digitized and coupled to two sampling circuits. By selectively sampling the encoded...
4688253 L+R separation system  
An L+R separation system separates the L+R component of a composite stereo signal, such as a BTSC signal or an FM broadcast stereo signal, from the L-R suppressed subcarrier component by sampling...
4578807 FM stereo multiplex demodulator  
A composite FM stereo multiplex signal is demodulated using a double-balanced switching circuit cooperating with current mirror circuits so that demodulation and separation of the multiplexed...
4569072 Clock-controlled filtering arrangement  
A clock-controlled filtering arrangement for suppressing a number of interference frequencies related to a clock frequency, which comprises a time-discrete comb filter included in a negative...
4560942 Demodulation circuit having triangular wave for blocking harmonics  
A demodulator circuit for demodulating a signal which varies substantially sinusoidally with time, such as a stereo signal having a carrier frequency, comprises a mixer circuit having a first input...
4539697 FM Stereo demodulating circuit  
An FM stereo demodulating circuit comprising a pulse counter detector 1 for generating a pulse train signal including the frequency spectrum of the FM signal, DC biasing means for current biasing...
4517520 Circuit for converting a staircase waveform into a smoothed analog signal  
In converting a staircase waveform signal into a smoothed analog signal, this circuit can perform the high-quality conversion without any sophisticated lowpass filter. An input staircase signal is...
4502148 FM Stereo demodulator for demodulating stereo signals directly from an FM intermediate frequency signal  
Disclosed is an FM stereo demodulator in which components of the demodulated signal corresponding to odd harmonics of the subcarrier signal are eliminated. In order to prevent the production of odd...
4497063 FM stereo demodulator  
An FM stereo demodulator having improved separation and distortion characteristics comprising a high-frequency pulse signal which is modulated by a sinusoidal subcarrier signal produced in...
4489430 FM Stereo demodulation circuit  
A pulse position modulated (PPM) signal is derived from an input FM signal, and first and second switching signals are derived which are opposite in phase and correspond to alternating half cycles...
4454607 FM Stereophonic receiver with CPU controlled tuning and demodulating  
An FM stereophonic receiver is arranged so that a central processing unit assigned for selection of a broadcasting station is burdened, based on a clock pulse of the central processing unit, to...
4435618 Adjacent station interference rejecting circuit  
A circuit for eliminating a beat signal resulting from interference between a broadcast signal of a received station and a broadcast signal of an adjacent station during the reception of an AM...
4433433 Sampling pulse forming circuit for FM stereo demodulator  
A sampling pulse generator circuit for a stereo demodulator circuit of a sample and hold system is disclosed. The pulse generator circuit uses pilot signals of an FM stereo broadcast as an input...
Matches 1 - 50 out of 104 1 2 3 >