Abstract: A media player system, method and computer program product are provided. In use, an utterance is received. A command for a media player is then generated based on the utterance. Such command is utilized for providing wireless control of the media player.

Abstract: A method of transmitting vocal/musical signal via 2.4 GHz or higher wireless communication includes the steps of collecting a vocal/musical signal from a microphone/musical instrument; modulating the vocal/musical signal via 2.4 GHz or higher band as radio frequency to form an uncompressed modulated signal; wirelessly transmitting the modulated signal through an audio streaming transceiver; demodulating the modulated signal into a digital signal; and converting the digital signal back to the vocal/musical signal in analog form to be outputted through the audio outputting device. The signal is uncompressed to keep CD-quality thereof and is transmitted in 2.4 GHz or higher band for preventing interference from other wireless equipments.

Abstract: Systems and techniques for digital processing of FM stereo signals are described. A carrier signal such as a 38 kHz carrier may be recovered and used to process a difference signal such as a left minus right signal. The left minus right signal and a left plus right signal may be used to generate separate left plus right signals.

Abstract: A stereo decoding system comprises an oscillator, a bandpass filter, a PLL unit and a stereo decoder. The oscillator generates a first signal with a center frequency. The bandpass filter receives a stereo multiplexed signal and the first signal to filter out a pilot signal. The PLL unit receives the pilot signal to generate a PLL output signal. The stereo decoder receives the stereo multiplexed signal and the PLL output signal to separate a left channel signal and a right channel signal from the stereo multiplexed signal.

Abstract: A decimator is used to process a multi-channel audio signal, and includes a memory, a controller and a processing unit. The processing unit is used to decimate each input audio component of a multi-channel audio signal to generate corresponding multi-channel operational data. The controller is used to control read and write actions for each audio component of the multi-channel audio signal and the multi-channel operational data into or from the memory. The memory provides a digital signal process for decimation together with the processing unit. The input of the multi-channel audio and the output of the multi-channel operational data are performed through time division. Compared with conventional decimator circuits, the decimator circuit of the present invention reduces the cost and the power consumption of the hardware circuitry.

Abstract: An integrated circuit chip is described. The integrated circuit chip includes an audio input section for accepting audio signal, a digital signal processing section for processing the audio signal to perform audio encoding and frequency modulating, a frequency modulation signal processing section for up converting and transmitting the digital signal processor processed signal as a radio frequency signal and a frequency synthesizer for providing desired frequencies.

Abstract: A stereo modulator converts an inputted audio signal to a stereo composite signal. A frequency modulator, which includes a PLL circuit, performs frequency modulation with the stereo composite signal outputted from the stereo modulator as being a modulation signal. A first programmable divider and a second programmable divider divide an external clock signal inputted from the outside by a first division ratio and a second division ratio set respectively and outputs. A first clock signal outputted from the first programmable divider is used as a reference clock signal for generating the stereo composite signal, and a second clock signal outputted from the second programmable divider is used as a reference clock signal of the PLL circuit.

Abstract: Stereo recovery circuitry for a digital receiver is disclosed that provides increased accuracy and efficiency in recovering stereo signal information from transmitted stereo signals. The stereo decoder includes a digitally controlled oscillator that recovers a pilot tone signal from transmitted stereo signal information. By processing demodulated stereo signals on the digital side and digitally controlling the oscillator, the stereo decoder has increased efficiency and accuracy. In one embodiment, the oscillator may be a phase-locked-loop having a loop filter and an amplitude stabilized tunable resonator. Additional circuitry is disclosed for utilizing the pilot tone signal to recover left and right channel signal information from the demodulated stereo signals.

Abstract: An RF receiver operates to receive broadcast RF signals that include at least one of an analog portion and a digital portion. The RF receiver performs processing of the analog portion and/or the digital portion to generate a digital path signal. The RF receiver performs further processing of the analog portion to generate a first audio signal. A digital modulation processing system may be electrically connected with the RF receiver. The digital modulation processing system may receive and process the digital path signal to generate a second audio signal. The RF receiver may selectively utilize at least one of the first audio signal and the second audio signal to generate an audio output.

Abstract: According to the invention, a circuit arrangement for gaining a 38 kHz stereo subcarrier and a 57 kHz RDS carrier for decoding a stereo signal comprised in a demodulated FM signal and/or an RDS signal comprised in a demodulated FM signal, having a simple structure with only one PLL and particularly only one voltage-controlled oscillator (2) is characterized in that the arrangement comprises a phase-locked loop with a loop filter (1), a voltage-controlled oscillator (2), a first phase detector (3) which receives a reference signal having a reference frequency, and a second phase detector (4), which receives the FM signal, the output signal of the voltage-controlled oscillator (2) being coupled to both phase detectors (3, 4) in a form divided down by means of dividers (6, 9; 10, 11), and the signal fed back to the second phase detector having a frequency of 19 kHz, in that dividers (9, 10, 12) are provided, by means of which the output signal of the voltage-controlled oscillator (2) is divided down and which su

Abstract: Frame synchronization of a received OFDM signal (such as that used in a hybrid FM DAB system) is provided by filtering out significant outer frequency portions of the digital channels, and then using cyclic extension and correlation of the cyclically extended bits (or samples). The received OFDM signal is passed through a bandpass filter to remove outer digital subcarriers (i.e., those farthest from a center frequency) from a received OFDM signal before correlating to locate the OFDM frame boundaries. By filtering out digital subcarriers within each of the digital channels, particularly those closest to adjacent channels and thus most likely to be interfered with by an adjacent first channel OFDM (or FM) signal, correlation between cyclically extended bit (or sample) patterns and thus frame synchronization of OFDM signals can be improved significantly.

Abstract: A stereo composite signal including a pilot signal is demodulated by processing input samples to obtain internal samples having variable sampling timings, synchronizing these sampling timings with the pilot signal, and digitally processing the internal samples to obtain stereo audio data. The internal samples may be obtained from the input samples by decimation or interpolation. Since the sampling frequency and sampling timing of the input samples do not have to be precisely controlled, no voltage-controlled oscillator is needed, and the demodulator can easily be incorporated into a monolithic integrated circuit.

Abstract: A method and system of audio synthesis capable of reducing CPU load is disclosed, which establishes a parameter look-up table in a read-only memory (ROM). When a computer system synthesizes audio signals, the required coefficients are obtained from the table, which relatively reduces the amount of parameter transferred between an audio chip and a central processing unit (CPU).

Abstract: A frequency modulation (FM) multiplex demodulation device is provided, in which the feeling of stereo is maintained excellent and the offensive noise to the ears can be reduced.

Abstract: A method and apparatus for minimizing multipath interference for commercial FM signals which use SCA secondary signals in QAM format that includes tracking the time series of phase measurements of a received stereo pilot signal for determining the proper phase reference for demodulation of QAM signals at the center of the time series. Phase measurements of the pilot signal are tracked over a predetermined tracking period. The phase measurement is used to support demodulation of the QAM signal. The SCA secondary signals in QAM format transmitted on commercial FM have minimal multipath interference and Doppler interference by movement of transmitter and receiver (vehicular).

Abstract: An arrangement for decoding a stereo multiplex signal, comprising a baseband sum signal (L+R), a difference signal (L−R) which is amplitude-modulated on a suppressed sub-carrier and a pilot signal having a frequency located between the frequency bands of said sum and difference signals, said arrangement having an input for the stereo multiplex signal coupled through parallel stereo sum and difference signal paths to first and second inputs of a dematrix circuit, a synchronous demodulator being included in the difference signal path, a local sinusoidal sub-carrier being supplied to a carrier input of said synchronous demodulator for a synchronous demodulation of said amplitude-modulated difference signal (L−R) into baseband.

Abstract: A wireless output input device (WOID) digital audio player for storing and/or receiving digital audio and preserving the digital stream without the inherent distortion of translating the stream to analog prior to modulation and transmission, which includes an FM receiver, and an FM transmitter for transmitting the audio to an external FM radio or receiver. The device automatically and periodically scans a plurality of channels on the FM band to determine the channel having the least amount of interference and then tunes the FM transmitter to the frequency of that channel and displays the channel to which the external receiver should be tuned. A remote control may be provided to selectively transmit signals to the player's FM receiver for controlling operation of the player.

Abstract: An FM stereo signal demodulating apparatus includes a bandpass filter 1 for extracting a 19 Hz signal from an FM detected signal; a first phase shifter 21 for phase-shifting the 19 Hz signal by 90 degree; a first XOR 22 for taking an exclusive OR between an output from the first phase-shifter 21 and the 19 KHz signal; a second phase shifter 23 for phase-shifting an output signal from said XOR 21; a second XOR 24 for taking an exclusive OR between an output from the first XOR 22 and an output from the second phase shifter; an inverter 25 for inverting an output from said XOR 24; a third phase-shifter for phase-shifting an output signal from said inverter 25; a third XOR for taking an exclusive OR between an output from said third phase-shifter 26 and an output from said first XOR 22; a first multiplier 3 for multiplying an output from said first XOR 22 and said FM detected signal; a second multiplier 4 for multiplying an output from said third XOR 27 and said FM detected signal; a third multiplier 5 for multip

Abstract: Stereo recovery circuitry for a digital receiver is disclosed that provides increased accuracy and efficiency in recovering stereo signal information from transmitted stereo signals. The stereo decoder includes a digitally controlled oscillator that recovers a pilot tone signal from transmitted stereo signal information. By processing demodulated stereo signals on the digital side and digitally controlling the oscillator, the stereo decoder has increased efficiency and accuracy. In one embodiment, the oscillator may be a phase-locked-loop having a loop filter and an amplitude stabilized tunable resonator. Additional circuitry is disclosed for utilizing the pilot tone signal to recover left and right channel signal information from the demodulated stereo signals.

Abstract: The noise in a frequency demodulated audio signal is detected on basis of the characteristics of the stereo-multiplex signal to obtain a very reliable information that can be used for the sliding stereo-mono transition, noise blanking and a de-noising of the stereo-difference signal. A noise signal (vd,l(t)−vd,u(t) or vd,u(t)−vd,l(t)) is calculated by subtracting one sideband of the stereo-difference signal from the other sideband of the stereo-difference signal and as a direct measure for the quality of the signal generating the variance (&sgr;2vd) of the noise signal by squaring and thereafter averaging the noise signal.

Abstract: A feedback controller, embedded in an FM audio processor, that controls the “integrated multiplex power” to the requirements of ITU-R 412 (2.51) is disclosed. This regulation specifies the maximum power, which is the same as the power produced by a sinewave modulating the carrier ±19 kHz (where ±75 kHz is 100% peak modulation). The controller applies the square of the multiplex signal to an integrator. A constant is removed from the integrator; representing the maximum power threshold. The output of the integrator is sampled periodically with a sample-and-hold circuit. A second integrator receives the output of the sample-and-hold. The output of the second integrator circuit is added to the threshold setting of a compressor, which determines the average power output of the compressor. The output of the compressor is applied through a peak controller to the input of the multiplex coder, closing a feedback loop, which controls the integrated multiplex power to a preset threshold.

Abstract: A feedback controller, embedded in an FM audio processor, that controls the “integrated multiplex power” to the requirements of ITU-R 412 (2.51) is disclosed. This regulation specifies the maximum power, which is the same as the power produced by a sinewave modulating the carrier ±19 kHz (where ±75 kHz is 100% peak modulation).

Abstract: The invention relates to a device for receiving digital radio signals. The device has a digital receiving appliance comprising a tuner and a demodulator that is connected to said tuner. The device also contains a first microcomputer. The demodulator and the first microcomputer are connected to a supplementary module by an appliance interface of the digital receiving appliance. Said supplementary module has a second microcomputer and a signal processing unit which is controlled by said second microcomputer and which is connected to the appliance interface at the output end. The supplementary module also contains at least one other signal output through which the signals that are processed in the signal processing unit can be output.

Abstract: The invention addresses itself to the task of providing a medium-frequency stereo broadcast receiving circuit that does not require any alteration of the radio wave format used in the medium-frequency stereo broadcast system that has become the de facto standard, and that receives transmitted broadcast waves and removes, in the course of the demodulation process, disturbance that has affected the signal during its propagation, thereby improving the audio quality of the demodulated signal and obtaining the full potential of the stereo effect. To achieve this, the received medium-frequency stereo broadcast wave is converted to a single-sideband signal, and the sum signal (L+R) is demodulated from the phase term of this converted single-sideband signal. The difference signal (L−R) is demodulated from the phase term of the received medium-frequency stereo broadcast wave and from the demodulated sum signal output.

Abstract: A method and apparatus for minimizing multipath interference for commercial FM signals which use SCA secondary signals in QAM format that includes tracking the time series of phase measurements of a received stereo pilot signal for determining the proper phase reference for demodulation of QAM signals at the center of the time series. Phase measurements of the pilot signal are tracked over a predetermined tracking period. The phase measurement is used to support demodulation of the QAM signal. The SCA secondary signals in QAM format transmitted on commercial FM have minimal multipath interference and Doppler interference by movement of transmitter and receiver (vehicular).

Abstract: A radio back-end circuit that includes an integrator and a first variable voltage translator having a signal input coupled to the output of the integrator circuit. Also included is a first variable low pass filter, a second variable voltage translator, and a variable attenuator. These components of the radio back-end circuit are communicatively coupled such that noise is reduced in radio communications and signal and reception range control is improved in certain situations.

Abstract: An enhanced radio graphic data system comprises an FM receiver, RDS demodulator and decoder, display, microprocessor and memory. The system incorporates a protocol enhancement of RDS involving the redefinition of several bits within the B-block. An accompanying arrangement utilizes data in the C- and D-Blocks to create message streams containing the text data to be presented along with associated formatting instructions.

Abstract: An FM stereo signal demodulating apparatus includes a bandpass filter 1 for extracting a 19 Hz signal from an FM detected signal; a first phase shifter 21 for phase-shifting the 19 Hz signal by 90 degree; a first XOR 22 for taking an exclusive OR between an output from the first phase-shifter 21 and the 19 KHz signal; a second phase shifter 23 for phase-shifting an output signal from said XOR 21; a second XOR 24 for taking an exclusive OR between an output from the first XOR 22 and an output from the second phase shifter; an inverter 25 for inverting an output from said XOR 24; a third phase-shifter for phase-shifting an output signal from said inverter 25; a third XOR for taking an exclusive OR between an output from said third phase-shifter 26 and an output from said first XOR 22; a first multiplier 3 for multiplying an output from said first XOR 22 and said FM detected signal; a second multiplier 4 for multiplying an output from said third XOR 27 and said FM detected signal; a third multiplier 5 for multip

Abstract: A digital FM signal generator allows the generation of a modulated FM signal for broadcasting without the need for an analog modulator. The signal generator includes a digital signal processor which receives left and right signals from left and right signal channels and interpolates the signals to create a composite base band signal. The composite base band signal is then used by a numerically controlled oscillator to modulate a digital carrier signal. The result is a digital modulated FM RF signal which is then converted to an analog signal for broadcasting.

Abstract: An apparatus and method is provided for transmitting “masked” stereo audio signals in a signal distribution network such as a cable television system within the bandwidth constraints of conventional frequency allocation schemes. In various embodiments, left and right stereo audio signal components (L+R and L−R) are used to amplitude modulate a carrier using independent sideband (ISB) modulation without the transmission of a pilot signal. A jamming signal or low bandwidth data signal may be transmitted in place of the normal pilot tone. Various aspects of the invention contemplate the use of Hilbert transforms to perform the ISB modulation and demodulation.

Abstract: The signal source of the reference frequency of a PLL 20 is composed of a VCO 24. A VCO 14 is provided. A first audio signal (L+R) is supplied to the VCO 24 so as to control its oscillation frequency f24. A second audio signal (L−R) is supplied to the VCO 14, so that an FM signal SSUB is formed whose occupied frequency band is outside the band of the first audio signal (L+R). This FM signal SSUB is supplied to an adder 26, hereby added to a phase comparison output that is supplied to a VCO 21 from a low-pass filter, and then supplied to the VCO 21.

Abstract: A 900 MHz wireless speaker system having a tuning system that is features a variable down conversion scheme provided by a phase lock loop system controlled by a microprocessor and an automatic frequency control circuit. The speaker system utilizes either a battery and/or AC power source and provides remote control of features on the speaker.

Abstract: A system (100) is provided wherein a primary radio signal and a redundant radio signal are transmitted from a transmitter subsystem (120) and received by a receiver subsystem (140). The output (112) of an audio source (110) is coupled to a modulator (160) for modulating a radio frequency signal (162) for coupling to a transmit antenna (172). A second output (114) of audio source (110) is coupled to a delay circuit (116), for adding a predetermined time delay thereto. The delayed audio source signal is coupled to a modulator (164) for modulating a second radio frequency signal (166) that is also coupled to the transmit antenna (172). The receiver subsystem (140) receives both the primary radio signal and the delayed redundant radio signal and couples each to a respective demodulator (180, 182). At least one demodulator (180) includes a circuit (181) for determining the degradation in the primary radio signal and provides a quality measurement output signal (186) to a blend control circuit (190).

Abstract: An oscillator circuit is provided for stabilizing the amplitude of a HF oscillation of an audio signal. In such an oscillator circuit, an audio signal having a frequency in the range of 20 Hz . . . 20 kHz is coupled into the oscillator circuit, is modulated with a high frequency and is emitted in the form of an RF audio signal having a frequency of more than 2 MHz. Such an oscillator circuit is used for instance in an infrared transmitting unit, wherein a low frequency audio signal is transformed into a higher frequency infrared signal. The higher frequency audio signals are transmitted via infrared channel to an appropriate receiving unit--for instance to infrared head phones--which comprises a receiving unit having an appropriate demodulator and preferably also a stereo-decoder in order to reproduce the low frequency audio signals.

Abstract: A system for transmitting a main channel signal, a first subcarrier signal, and a second subcarrier signal includes a control signal generator for producing a control signal in response to the amplitude of the main channel signal and the first subcarrier signal, a modulator coupled to the control signal generator and generating the second subcarrier signal, a voltage controlled amplifier for providing the second subcarrier signal at an injection level that varies with the control signal, and a transmitter for transmitting the second subcarrier signal at the varying injection level.

Abstract: 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 digital input signal so that its sampling frequency is equal to either a frequency of a subcarrier of a composite audio signal or a first sampling frequency of a first sampling signal for the operation of a composite audio signal generator, a sampling signal generator for generating the first sampling signal for the operation of the composite audio signal generator having the first sampling frequency which is equal to 2.sup.

Abstract: A circuit arrangement for converting of a stereo signal having a mid-plane signal and a side signal into an output signal for each of two audio signal channels. By this circuit arrangement, a simplified and also automatic crosstalk cancellation is possible.

Abstract: A digital audio broadcast receiving apparatus that minimizes a frequency at which the user switches between NICAM audio and analog audio. When a reserve audio switching flag C4 is "H" it indicates that analog audio and NICAM audio represent the same program, in which NICAM audio, which provides better sound quality, is automatically selected. If a broadcast receiving condition deteriorates, analog audio is automatically selected. Conversely, when the flag C4 is "L", it indicates that NICAM audio and analog audio represent two different programs. In this case, analog audio that is in synchronization with video is automatically selected. At this moment, it is possible that the user intentionally selects NICAM audio, which is not related to video, so that NICAM audio is not switched to analog audio even if NICAM audio has some noise. An audio switching point is shifted by changing a threshold for determining PCM data error rate or by changing a sampling time.

Abstract: Systems, methods and apparatus are provided for conducting local wireless audio signal transmissions from a local audio signal source to a person within a local signal transmission area. In certain embodiments, the transmissions are conducted over the 900 MHz local transmission band to a portable receiver unit supported on the headband of a stereo headphone unit. The receiver unit serves to down convert the 900 MHz signal to a local frequency band which is received by an FM receiver of the receiver unit which serves to reproduce the audio signals therefrom which are, in turn, converted to acoustic signals by electroacoustic transducers of the headphone. A transmitter unit includes a ceramic resonator stabilized FM transmitter, as well a filter for suppressing high frequency noise in an audio modulation signal, a stereo audio multiplexing unit utilizing a 3f.sub.H subcarrier and an overmodulation detection unit.

Abstract: A stereo/multivoice recording and reproducing apparatus used for a high fidelity video tape recorder comprises a multi-channel television system (MTS) decoder for demodulating stereo and multivoice signals included in an IF signal supplied from a tuner, a high fidelity audio processor for frequency-modulating the stereo signal output from a MTS decoder, left and right channel heads for recording the stereo signal frequency-modulated in the high fidelity audio processor, a second audio processor for amplifying the multivoice signal from the MTS decoder, and a third audio head for recording the multivoice signal amplified in the second audio processor. According to one aspect of the invention, the apparatus can simultaneously record stereo and multivoice signal and selectively reproduce one of the stereo signal and the multivoice signal.

Abstract: A method and apparatus are provided for transmitting, receiving, and reproducing digital audio signals as discrete carriers similar to standard FM broadcast signals. An audio signal is digitized using, for example, adaptive delta modulation techniques. Several channels of audio information, such as left and right stereo channels and a second audio program ("SAP") channel can all be digitized and incorporated onto the digital broadcast signal carrier. The digitized audio signal may be modulated using multiphase modulation of the carrier of an FM broadcast band or cable television band signal. A plurality of audio channels may be digitized and transmitted over the airwaves, or over a cable transmission network. Channels of nondigitized audio channels may be interspersed with the digitized audio channels in the Fm broadcast band.

Abstract: A broadcast and reception system provides a segmented broadcast signal for providing regional traffic information and a receiver adapted to receive selected segments of that broadcast. The segmented broadcast signal includes a number of segments which each include a tone sequence, a digital regional code, a digital duration code, and an audio segment. The receiver monitors selected regional traffic segments and converts the selected audio segment to a form compatible with a standard automotive radio. Thus, a user can selectively monitor regional traffic information without having to listen to reports from regions of no interest to him. Alternatively, the selected traffic information can automatically override normal radio listening.

Abstract: A synchronized broadcast network comprises a main transmitter transmitting an audio source signal to a plurality of receiver/transmitter units remote from each other and from the main transmitter, the receiver/transmitter units broadcasting the audio signal using frequency modulation. In the main transmitter the audio source signal is digitized by sampling it at a predetermined sampling frequency. A digitized signal representing the sampled audio signal is transmitted to the receiver/transmitter units. In each receiver/transmitter unit a reference signal representing the sampling frequency is derived from the received digitized signal and the received digitized signal is passed through a succession of digital processing stages including a stage in which a carrier derived from the reference signal is digitally modulated and a stage in which the result of the digital modulation is digital-to-analog converted.

Abstract: An FM stereophonic receiver including an FM detector circuit for detecting an intermediate frequency signal, and for providing a main signal and a sub signal in response to the detected intermediate frequency signal, a first high cut circuit, connected to receive the main signal, for providing a first high cut signal, a high cut control circuit for providing a high cut control signal in accordance with a received signal field strength level, the first high cut circuit controlling a frequency characteristic of the main signal in accordance with the high cut control signal, a second high cut circuit for providing a second high cut signal, a separation control circuit for providing a separation control signal in accordance with the received signal field strength level, the second high cut circuit controlling a frequency characteristic of the sub signal in accordance with the separation control signal, and a stereophonic demodulation circuit for providing separated right and left channel signals.

Abstract: Movable and audible toys and other animated devices spaced apart from a television screen are provided with program synchronized audio and control data to interact with the program viewer in relationship to the television program. A sampling keyboard-based encoder for kinetic device actuating signals is coupled via an audio mixer to an audiovisual programming source and television transmitter carrying an audio based kinetic and audio signal complex. At a remote location, coded audio and kinetic device signals along with audiovisual programming is received and the audiovisual programming content is displayed for viewing and listening. Stereo soundband based program audio signals are decoded and separated from the stereo sound band based device audio and kinetic signals. The device audio and kinetic signals are retransmitted to a spaced apart toy causing the device to be audible and move in synchronization with the spaced apart audiovisual programming.

Abstract: In order to permit three-component (left, right and back) audio signals (LS, RS, BS) to be conveyed by a three-channel (left, right and mono) transmission system and still permit stereo and mono compatibility, the signals are encoded so that the three channels carry LS-1/2BS, RS-1/2BS and LS+RS+BS, respectively. Upon receipt, the signals can be decoded back to LS, RS and BS respectively. In a mono receiver without such a decoder, the signal LS+RS+BS on the mono channel is employed, and in a stereo receiver the signals LS-1/2BS and RS-1/2BS on the stereo channels are employed.

Abstract: 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 extracted from an FM-demodulated output; a subcarrier signal is formed, based on this pilot signal; IF signals are switched intermittently by this subcarrier signal; and intermittent IF signals are IF-detected to obtain intermittent signals of base-band signals.These intermittent signals are switched by means of two switches, based on a subcarrier signal. Low frequency components of each output audio signal are extracted to obtain left and right signals EL and ER through a de-emphasis circuit.Owing to this device, it is possible to enlarge a reception region for an FM stereo broadcast with a high sensitivity.

Abstract: An FM stereo receiver for receiving FM stereo broadcast signals includes a pro-logic surround system in which the left stereo signal, a right stereo signal, a stereo sum signal and a stereo difference signal are selectively emphasized. Also includes a noise signal detector for detecting the noise signal in the received signal, and a device for disabling the pro-logic surround system when the noise signal is detected.

Abstract: Method and apparatus are provided for transmitting, receiving, and reproducing digital audio signals as discrete carriers similar to standard FM broadcast signals. An audio signal is digitized using, for example, adaptive delta modulation techniques. Several channels of audio information, such as left and right stereo channels and a second audio program ("SAP") channel can all be digitized and incorporated onto the digital broadcast signal carrier. The digitized audio signal may be modulated using multiphase modulation of the carrier of an FM broadcast band signal. A plurality of audio channels may be digitized and transmitted over the airwaves, or over a cable transmission network. Channels of nondigitized audio channels may be interspersed with the digitized audio channels. Source material for the digitized audio channels may be provided to a cable headend over the cable transmission network outside the FM band, and rebroadcast over the cable transmission network in the FM band.

Abstract: For a digital/analog master control desk for audio signals, it is proposed to sum the analog channel signals, possibly while simultaneously processing them. Forming the analog broadcast signal, this sum is added to a further channel signal A.sub.n which is formed of the analog-converted sum of the digital channel signals. A digital signal D.sub.n obtained from the digital-converted sum of the analog channel signals is added to the sum of the digital channel signals, resulting in a digital broadcast signal which has the same modulation content as the analog broadcast signal.