Abstract: Described is a transmission system (10) comprising a transmitter (12) for transmitting a narrowband audio signal to a receiver (14) via a transmission channel (16). The receiver (14) comprises a frequency domain bandwidth extender (18) for extending a bandwidth of the received narrowband audio signal by complementing the received narrowband audio signal with a highband extension thereof. The bandwidth extender (18) comprises an amplitude extender (24) for extending the bandwidth of an amplitude spectrum of the received narrowband audio signal by mapping narrowband amplitudes onto highband amplitudes. The bandwidth extender (18) further comprises a phase extender (26) for extending the bandwidth of a phase spectrum of the received narrowband signal and a combiner (28) for combining the extended amplitude spectrum and the extended phase spectrum into a bandwidth extended audio signal.

Abstract: An AM/FM DIF radio has an IF to audio converter that provides an audio signal from an IF signal responsive to a clock signal. During the processing of the IF signal, a spurious signal is intentionally generated. The spurious signal is based on the predetermined offset which is included in the IF signal applied to an A/D converter. The predetermined offset is greater than or equal to half of the AM bandwidth and less than or equal to the system bandwidth. The spurious signal is generated at a frequency proportional to the sum of an imprecision offset and the predetermined offset. A low pass filter removes the spurious signal while preserving the desired portion of the audio signal.

Abstract: The wide bandwidth transceiver includes a receiver section, a transmitter section, and a local oscillation module. The receiver section includes a 1st receiver intermediate frequency (IF) stage, a receiver switch module, and a 2nd receiver IF stage. The 1st receiver IF stage is operably coupled to convert a 1st inbound radio frequency (RF) signal into a 1st inbound IF signal based on a 1st local oscillation of the local oscillation module. The receiver switch module passes either the 1st inbound IF signal or a 2nd inbound RF signal, which have similar carrier frequencies, to the 2nd receiver IF stage. The 2nd receiver IF stage receives the selected signal from the receiver switch module and based on a 2nd local oscillation converts the selected signal into a low intermediate frequency signal. The transmitter section includes a 1st transmitter intermediate frequency (IF) stage, a 2nd transmitter IF stage, a power amplifier and a transmitter switch module.

Abstract: A remote signaling receiver system includes a receiver that operates in two different modes of demodulation to accommodate different types of signals from different types of transmitting devices. A first demodulator, preferably an ASK demodulator, is adapted to process signals from a signal transmitter that generates a first type of signal. A second demodulator, preferably one that is not sensitive to amplitude modulation such as a FSK demodulator, is adapted to process signals received from at least one other type of device, which provides a second type of signal. A system designed according to this invention is particularly useful as a remote keyless entry system for a vehicle where one or more sensors are provided on the vehicle to provide an indication of a chosen condition of one or more of the vehicle components.

Abstract: A wireless transmission device for communicating a plurality of audio streams to remote devices may include a plurality of inputs for receiving a plurality of digital audio streams, a combiner connected to the inputs for combining control codes and the received audio streams in a predetermined format to form a signal wherein the control codes for controlling the operation of a remote device equipped for processing the signal to extract the audio streams therefrom in accordance with the predetermined format, and a transmitter connected to the combiner to transmit the signal for reception by the remote device. The transmitter may include an infra-red light emitter for transmitting the signal as an infra-red light signal.

Abstract: A system 100 including a radio receiver 101/108 and switched mode circuitry 114/115 operating at a selected switching frequency is disclosed. Circuitry 207–209 sets the switching-circuitry of the switched mode circuitry 114/115 as a function of a frequency of a signal being received by a radio receiver 101/108.

Abstract: A wireless audio distribution system having a wireless transmitter, responsive to a plurality of audio input channels, for transmitting a encoded digital bitstream serially combining each of the audio input channel, the encoded digital bitstream further including control data disbursed therein, a receiver, responsive to the transmitted encoded digital bitstream, for decoding and demultiplexing the digital bitstream, a manual selector switch, connected to the receiver device for selecting one or more of the audio input channels to be reproduced, and a sound producing device for selectively reproducing the one or more selected audio channels in accordance with the control data.

Abstract: A analog/digital modulation type discrimination circuit 1 discriminates whether a reception signal is an analog modulation type, a linear modulation type or a non-linear modulation type by digital modulation type. In case where the reception signal is discriminated to be the analog modulation type, an analog modulation type discrimination circuit 2 discriminates whether it is an AM signal or an FM signal among the analog modulation type. In case where the reception signal is discriminated to be the linear modulation type by digital modulation type, a linear modulation type discrimination circuit 3 discriminates whether it is a BPSK signal, a QPSK signal, a ?/4-shift QPSK signal, an 8-PSK signal, an M-ary PSK signal of multi-level exceeding 8-levels, a 16 QAM signal or a n M-ary QAM signal of multi-level exceeding 16-levels among the linear modulation type by digital modulation type.

Abstract: In a method of operating a remote control system and in such a system comprising an RF transmission and receiving system and an IR transmission device the sub-carrier information of the IR signal is transmitted in the RF signal in a signal separate from the envelope information of the IR signal which is contained in a envelope signal.

Abstract: A method of identifying a signal type uses parameters of the signal as a basis for automatic identification. A signal of interest is selected from a display of a spectral waveform for a specified frequency. An occupied bandwidth for the signal of interest is estimated and, if the occupied bandwidth is common to more than one known signal type, a complementary cumulative distribution function of peak power for the signal of interest is estimated. The signal type may be identified as a function of these parameters. Additionally the frequency of the signal of interest may be compared with a database of spectral assignments for known signal types to provide further information about the signal of interest.

Abstract: A pin layout which prevents degradation of a frequency characteristic of a low noise amplifier and a receiving mixer included in a semiconductor integrated circuit for dual-band transmission/reception wherein the circuit of the low noise amplifier is provided at a position where the distance from the end of a pin outside the package of the low noise amplifier to the pad is the shortest; ground pins of two low noise amplifiers and the high frequency signal pins are arranged respectively so as not to be adjacent to each other; the power source and ground pin of the low noise amplifier, and the power source and ground pin of the bias circuit are respectively separated; and high frequency signal wires do not intersect each other.

Abstract: A scanning antenna diversity system for mobile FM radio having an antenna system with controllable logic switch (2), wherein a different high-frequency reception signal (5), in terms of diversity, is passed to a receiver (3). An IF signal (9), derived from this reception signal turns on a diversity processor (4), which switches the logic switch (2) into a different switching position in response to reception interference. The diversity processor (4) has a first interference detector (6) whose momentary interference indicator signal (10) is obtained without delay from the momentary value of the IF signal (9), which is limited to the IF bandwidth, by means of determining the interference-related occurrence of impermissible momentary values of the frequency and amplitude of this signal.

Abstract: A receiver in which the sneaking noise from a crystal oscillator is reduced. A high-frequency amplifier circuit 11, a mixing circuit 12, a local oscillator 13, intermediate-frequency filters 14 and 16, an intermediate-frequency amplifier circuit 15, a limit circuit 17, an FM detection circuit 18, and a stereo demodulation circuit 19, an oscillator 20, and a PLL circuit 21 all constituting an FM receiver are provided as a one-chip component 10. A crystal oscillator 31 as an external component is connected to the oscillator 20. The natural-oscillation frequency of the crystal oscillator 31 is so set that the fundamental component and its harmonics are out of the reception band.

Abstract: In a receiver, either an FM/AM signal to be used for a keyless entry system or a high frequency signal to be used for an automobile audio system for FM broadcast is applied to a first converter. An IF limiter amplifier amplifies the output signal of the converter and subsequently limits the amplitude of the output signal to a predetermined level. An FM detector circuit FM-detects the output signal of the IF limiter amplifier. A stereophonic demodulation circuit demodulates the output signal of the detector circuit. A high frequency signal for AM broadcast is fed to an IF amplifier by way of a second converter. Either the output signal of the IF limiter amplifier or that of the IF amplifier is applied to an AM detector circuit.

Abstract: A pin layout which prevents degradation of a frequency characteristic of a low noise amplifier and a receiving mixer included in a semiconductor integrated circuit for dual-band transmission/reception wherein the circuit of the low noise amplifier is provided at a position where the distance from the end of a pin outside the package of the low noise amplifier to the pad is the shortest; ground pins of two low noise amplifiers and the high frequency signal pins are arranged respectively so as not to be adjacent to each other; the power source and ground pin of the low noise amplifier, and the power source and ground pin of the bias circuit are respectively separated; and high frequency signal wires do not intersect each other.

Abstract: A demodulator has a resistor and a capacitor that may be subject to tolerances. For tolerance correction, the FM demodulator is preferably supplied with a reference frequency, which corresponds to the nominal mid-frequency of the demodulator, which is a function of the resistor and the capacitor. Any discrepancy between the actual mid-frequency of the demodulator and its nominal mid-frequency leads to the production of a voltage that differs from a nominal voltage at the output. A detector detects this error and adjusts the values of the resistor or capacitor until the error between the nominal voltage and the voltage is zero or is a minimum. The described principle can be used, for example, in integrated mobile radio receivers.

Abstract: A wireless speaker apparatus for a radio communication device includes a receiver front end to receive two RF carrier signals with audio information. A tunable filter circuit provides a low side and high side frequency response slope to slope demodulate the carrier frequencies to provide respective amplitude modulated output signals. A control signal tunes a center frequency of the tunable filter circuit to center one of the low or high side frequency response slopes near its associated carrier frequency while decentering the other frequency response slope from its carrier frequency so as to favor demodulation of the former modulated output signals over the latter. An audio back end converts the amplitude modulated output signals to audio. This same simple apparatus can be used for either left or right channel audio signals depending on the control signal.

Abstract: A direct conversion receiver for receiving a first input signal and directly downconverting it to baseband frequencies. The receiver includes a frequency translator which is responsive to a phase-split input signal having 2n components, wherein n is an integer greater than 1. The phase-split signal has a period T which is about n times the period of the first input. The frequency translator alternates, at a rate of about 2n/T, between switching the first input signal to a first output, and switching the first signal to a second output. A preprocessor is available to improve the switching characteristics of the phase-split input signal.

Abstract: A resonance chamber with two or more speakers positioned in the lid of a commercially available cooler chest and electrically connected to a radio circuit board also positioned in the lid and powered by a solar panels or a combination of solar panels and batteries. All elements are water proofed and positioned for protection during normal use of the cooler and positioned so as to not disrupt the normal use of the cooler.

Abstract: Described is a closed-loop power detector/controller for wireless systems employing a non-constant amplitude envelope modulation scheme. Any AM component in the feedback signal resulting from non-constant amplitude envelope signals is eliminated via feed-forward cancellation of the envelope signal. Generally, a signal representative of the AM variation in the non-constant amplitude envelope signals prior to amplification is obtained. This AM variation signal is then used to cancel any AM component in the feedback signal resulting from the non-constant envelope to create a power amplifier control signal without any AM variation, only the desired ramp profile.

Abstract: A method, apparatus, and computer instructions for controlling presentation of an audio broadcast. Presentation of the audio broadcast is ceased in response to detecting a mobile phone call. The audio broadcast is recorded to form recorded audio presentation data in response to detecting the mobile phone call. The recorded audio presentation data is presented when the mobile phone call ends.

Abstract: This invention includes a wireless transmitter comprising an IF-signal generator that modulates input signals into those of an intermediate frequency band, signal distributors that distribute signals from the IF-signal generator, and a plurality of signal-transmission units that convert the signals distributed by the signal distributors into those of a radio frequency band, and then transmit the converted radio signals. The invention also includes a wireless receiver that receives the radio-frequency-band modulated signals and restores the signals of the intermediate frequency band. In this way, effective diversity is realized and signal interruptions are prevented. In addition, a handy, low-cost wireless communications system is provided.

Abstract: An audio production, satellite uplink and radio broadcast studio system includes an audio console having a supporting meter bridge and editing unit operative under the control of a central or main computer. The audio console is coupled to a plurality of analog audio information sources including a plurality of microphones, a plurality of telephone lines, a radio broadcast tuner and a plurality of audio tape drives. The audio console is further coupled to a plurality of digital information sources including a pair of ISDN lines, a plurality of compact disc players, a mini-disc player and a remotely operated digital audio recorder. The computer is coupled to the audio console via an interface and sound card. The audio console is coupled to a plurality of program outputs having different program format capabilities and to a distribution amplifier operative to control the various remotely operated recording apparatus within the system.

Abstract: When a digital broadcasting channel and an analog broadcasting channel, over which the same program is currently being transmitted, are provided by a broadcasting station, upon each depression of a digital/analog switching button on an operating unit, an MPU alternately switches between the digital broadcasting channel and the analog broadcasting channel across which the program is being transmitted. And when the current broadcasting station provides a digital broadcasting channel and an analog broadcasting channel across which the same program is currently being transmitted, the MPU alternately switches between a predetermined digital broadcasting channel and a predetermined analog broadcasting channel.

Abstract: A common intermediate frequency broadcast radio front end. The invention employs a common front end that employs a common mixer and intermediate frequency for both AM and FM radio signals. Borrowing on the inherent advantages of employing a substantially reduced intermediate frequency, when compared to the elevated intermediate frequency that is employed in many conventional systems, the invention provides for the ability to employ components whose precision is significantly relaxed and whose cost is substantially reduced. The low frequency affords the ability to use relatively cheap ceramic filters and integrated filters within the IC instead of relatively expensive crystal filters commonly employed at higher intermediate frequencies. In addition, the implementation of a common mixer for both AM and FM signals results in a savings of real estate on the silicon die used to operate certain embodiments of the invention.

Abstract: A tire monitor for monitoring a characteristic of tires on a vehicle includes a circuit configured to receive a first wireless signal having tire characteristic data and a first wireless protocol. The circuit is further configured to receive a second wireless signal having tire characteristic data and a second wireless protocol. The second wireless protocol is different than the first wireless protocol. The circuit is configured to monitor first tire data on the first wireless signal and second tire data on the second wireless signal.

Abstract: An antenna circuit which is improved the deterioration of amplitude characteristic in a strong electric field, an antenna circuit for AM broadcasting which can surely inhibit and damp FM-band signals in the strong electric field and amplifies to output AM-band signals, and an antenna circuit for AM/FM broadcasting in which AM-band signals are not damped by means of an FM-band filter. In the first antenna circuit, the output signal of an antenna (10) is supplied to the base of a transistor Tr2 forming a current amplification type amplifier having a high-input and low-output impedance and the emitter of the transistor Tr2 is grounded through a coil L6 and connected to an FM receiver (16) through a band-pass filter (38). In the second antenna circuit for receiving AM broadcasting, an input terminal is connected to an AM amplifier circuit (36) through coils (L7) and L8 in series and to the gate G of a field effect transistor FET.

Abstract: A receiver for receiving a digital radio broadcast in which additional information is multiplexed with audio information includes a memory for storing the additional information, an LCD, and a bookmark button. When the bookmark button is depressed during reception of a program, a control unit stores additional information of the program in the memory as bookmark data. The bookmark data stored in the memory is displayed on the LCD. When data, for example, “Modern Jazz”, is specified as search data, the control unit sequentially searches programs currently being broadcast or programs to be broadcast later, detecting and tuning in to a program which includes the search data in the additional information thereof. Alternatively, the additional information of the detected program is displayed on the LCD, tuning in to the program in accordance with an operation by the user.

Abstract: A pin layout which prevents degradation of a frequency characteristic of a low noise amplifier and a receiving mixer included in a semiconductor integrated circuit for dual-band transmission/reception wherein the circuit of the low noise amplifier is provided at a position where the distance from a end of the pin outside the package of the low noise amplifier to the pad is the shortest; ground pins of two low noise amplifiers and the high frequency signal pins are arranged respectively so as not to be adjacent to each other; the power source and ground pin of the low noise amplifier, and the power source and ground pin of the bias circuit are respectively separated; and high frequency signal wires do not intersect each other.

Abstract: An ADSL front end is implemented with an adaptive AM interference canceller to cancel out either a carrier signal of an interfering AM radio signal, or a carrier signal and its sidebands of an interfering AM radio signal, from a received ADSL signal. By canceling an interfering AM radio signal rather than simply filtering out the relevant interfered with frequency band, the interfered with frequency band remains useable for ADSL transmission. In one embodiment, a reference AM radio receiver is either fixedly or adaptively tuned to the carrier frequency of an interfering AM radio station, and the received signal in the frequency band surrounding that carrier frequency is digitized and provided to an adaptive interference canceller. The adaptive interference canceller adaptively adjusts a time delay and phase of the generated AM interference signal to optimize cancellation at a hybrid of the same AM radio signal received as interference over a subscriber line.

Abstract: An intelligent radio apparatus that is adapted to receive Web radio broadcasts is disclosed. The Web Radio provides a user interface that is less like a computer program and more like a conventional radio, thus making the device easy to use. Rather than the complicated user interface found on Personal computers, the intelligent radio provides familiar radio-type user controls such as switches, a tuning knob, joysticks, cursor controls, voice activated controls, etc. The radio-type user controls allow the user to select a Web radio station and control other aspects of the operation of the intelligent radio in a manner that is more like a conventional radio and less like a computer program. The intelligent radio is configured to run the software needed to access the Internet and thus relieves the user of complicated software installation tasks such as installing and configuring an operating system and installing and configuring Internet access software.

Abstract: A process for synchronization of an input signal (S) involves demodulating (5a) the input signal (S) according to a particular demodulation method (AM) using a particular signal parameter for creation of a demodulated input signal (SAM); correlating (6a) the demodulated input signal (SAM) with a comparison signal (f (AM,Signal)) which depends on the demodulation method (AM) to determine a time offset (&tgr;) between the demodulated input signal (SAM) and the comparison signal (f (AM,Signal)); and time displacing, or shifting, the input signal through the time offset (&tgr;) calculated from the correlation.

Abstract: The present invention provides an AM modulated wave eliminating circuit which is capable of extracting a digital modulated wave by cancelling an AM modulated wave from an AM data multiplex modulated wave.

Abstract: A digital signal processing architecture for an audio system combines multiple functions in programmable and reconfigurable blocks to achieve an efficient use of hardware and chip area. AM, FM, and audio functions can be performed using the same reconfigurable hardware while taking into account the different sample rates and processing functions required for each.

Abstract: A receiving circuit includes: an antenna for receiving signal waves of two different frequency hands; a first receiving circuit for receiving a first receiving signal having a frequency; a second receiving circuit for receiving a second receiving signal having another frequency; a switch element for switching a signal path from the antenna to either one of the first receiving circuit and the second receiving circuit; a first diode; a second diode; and reverse bias voltage applying elements, each connected in parallel with one of the first diode and the second diode. The switch element is connected to a direct current power supply, and the switch element controls the connection of the direct current power supply such that the first diode and the second diode are biased in the forward direction when the first receiving signal is received and the first diode and the second diode are biased in the reverse direction when the second receiving signal is received.

Abstract: A dual-band radio monitoring apparatus which provides the reception of transmissions on commercial AM/FM frequency band(s) to be monitored and interrupted by transmission(s) on a controlling VHF/UHF frequency band(s), especially for use by motor vehicle racing fans so that they may have a continual AM/FM reception which is muted for reception of the controlling VHF/UHF transmission of conversation between the race car driver and his pit crew.

Abstract: A receiver for receiving reception signals of a first type, for example, TV signals, and reception signals of a second type, for example, FM-radio signals. The receiver may be used in multimedia applications. In the receiver, a single tuner TUN frequency converts a reception signal RFS into an intermediate frequency signal IFS. For relatively small-size implementations, the receiver is a single conversion receiver for both types of reception signals, the single conversion being effected in the tuner TUN. Depending on whether a first-type or second-type reception signal is desired, the tuner TUN provides the intermediate frequency signal IFS at a first intermediate frequency IF1 or a second intermediate frequency IF2, respectively. The intermediate frequency signal IFS at intermediate frequency IF1 is processed in a first intermediate frequency signal processor IFSP1.

Abstract: A messaging receiver (400) and corresponding system (100b) and method adaptable to a plurality of modulation formats including; a processor (401) having flexible resources (404), preferably software based, for receiving a signal to provide a modulation identifier, and a controller (403), coupled to the processor, for deploying the flexible resources responsive to the modulation identifier. Alternatively the messaging receiver includes a buffer (412) for storing a signal having a modulation format, and the processor processes the signal in accordance with the plurality of modulation formats so as to differentiate the modulation format, and the controller deploys the flexible resources responsive to the modulation format.

Abstract: A technique for reducing FM intrusion in an AM section of an AM/FM receiver. In one embodiment, a first switch is provided between an FM tuner filter circuit and an AM tuner circuit. A second switch is provided between the FM tuner circuit and a reference potential. When the receiver is in an FM mode, the first switch is closed so that a tuning voltage can be applied to the FM tuner circuit, and the second switch is open to prevent the tuning voltage from being affected by the reference potential. When the receiver is switched to the AM mode, the first switch is open to prevent intermodulation product signals generated by the FM tuner circuit from reaching the AM tuner circuit, and the second switch is closed to connect the FM tuner circuit to the reference potential. By connecting the FM tuner circuit to the reference potential when the receiver is in the AM mode, the tuning of the FM tuner circuit is shifted out of the FM bandwidth, thus eliminating intermodulation products at the AM frequencies.

Abstract: A broadcasting signal receiving apparatus includes a first signal receiving portion for receiving selectively frequency-modulated broadcasting signals to obtain a frequency-modulated intermediate frequency signal, a first band pass filter through which the frequency-modulated intermediate frequency signal passes, a first demodulator for frequency-demodulating the frequency-modulated intermediate frequency signal to obtain a first demodulation output signal, a second signal receiving portion for receiving selectively amplitude-modulated broadcasting signals to obtain an amplitude-modulated intermediate frequency signal, a second band pass filter through which the amplitude-modulated intermediate frequency signal passes, a second demodulator for amplitude-demodulating the amplitude-modulated intermediate frequency signal to obtain a second demodulation output signal, an output portion for obtaining a reproduced information output based on one of the first and second demodulation output signals, a signal supplyi

Abstract: A shortwave amplitude modulated broadcast converter having an antenna electrically connected to an output. The antenna functions to collect shortwave electromagnetic energy. Invention further includes a preselector having an input and an output. The preselector is electrically connected to an input to the antenna at an output and functions to filter unwanted noise from the antenna signal. A mixer having at least one input and an output is electrically connected to the preselector output at an input. The mixer functions to combine the filtered antenna signal and a band select signal to an output. A variable frequency oscillator having an output is electrically connected to a mixer input. The variable frequency oscillator frictions to provide a mixing frequency to the mixer. An output amplifier, having an input and an output, is electrically connected to the mixer and an input, where the output amplifier functions to amplify the combined antenna and variable frequency oscillator signals.

Abstract: A spread spectrum modulating and demodulating apparatus which is capable of providing FSK or PSK spread spectrum communications. In a transmitting device an input information signal is fed either to an oscillator or to a side of a power supply which is in turn connected to an operation device. An oscillator produces a carrier frequency signal which multiplied by a multiplier by the predetermined integer N1. A frequency divider divides the frequency of the carrier by a predetermined integer N2. A spread code generator uses an output signal of the frequency divider as a clock signal, and generates a spread code which is fed to the operation device. A switch selectively feeds an input information signal to either the oscillator for frequency shift keying the oscillator or through the side of the power supply connected to the operation device will effect a phase shift key operation.

Abstract: To differentiate between different types of modulation, a fast RSSI detector performs a RSSI measurement on a received signal. The output of the RSSI detector is sampled over a sampling window and generates sampled values. A processor calculates absolute values of piecewise first derivatives of the sampled values and sums the result to create a summation constant. A modulation detector determines the type of modulation based on the value of the summation constant and an RSSI compensation calculates a compensation factor to correct the RSSI measurement.

Abstract: Components for analog or digital input signals are in each case connected by switchable means to a controllable oscillator. The switch condition of the switchable means is set automatically and/or manually as a function of the input signal.

Abstract: A broadcasting system discriminating television receiver including a circuit for evaluating the output of an FM demodulator, a circuit for evaluating the output of an I/Q wave detector, and a controller for controlling a switch based on the results of each evaluation. The switch is used primarily to determine whether the output of the receiver is analog or digital.

Abstract: An automatic emergency alarm reception apparatus for a broadcasting receiver which has a radio frequency part and a low frequency part, comprising an ON/OFF switch connected between the radio frequency part and the low frequency part, for turning on the broadcasting receiver when a specific frequency signal indicative of a state of emergency is received at an antenna of the broadcasting receiver, and an emergency alarm signal detection circuit for detecting the specific frequency signal from the radio frequency part to control the ON/OFF switch. The emergency alarm signal detection circuit includes an air defense alarm signal detection part and an air-raid alarm signal detection part. The air defense alarm signal detection part is provided with a band pass filter, a level comparator, an inverter, a pulse generator and a counter. The air-raid alarm signal detection part is provided with first to third band pass filters, first to third level comparators and a sequential detector.

Abstract: A communication device which is capable of automatically discriminating whether a received signal is a carrier-wave-modulated signal or a single-pulse-modulated signal and obtaining a corresponding demodulated signal, thereby reducing a burden to a user in using the device. The device comprises a demodulating circuit for demodulating a carrier-wave-modulated signal, a demodulating circuit for demodulating single-pulse-modulated signal, a switch circuit for selecting either of two demodulating circuits and a carrier detecting circuit for detecting the presence or absence of a carrier-frequency component of the carrier-wave-modulated signal, characterized that the switch circuit selects an output of the demodulating circuit for the carrier-wave-modulated signal when the carrier of the carrier-wave-modulated signal is detected by the carrier detecting circuit.

Abstract: A dual-band radio receiver utilizes a single transformer to provide impedance matching between signal mixers from separate signal paths to their respective intermediate frequency filters. Thus, a dual-band radio receiver can be made eliminating one transformer and the printed circuit board space of one transformer. In addition, only one transformer needs to be frequency aligned or adjusted during manufacturing.

Abstract: An improved tuner for a varactor-tuned local oscillator in a radio receiver includes a winding of a pair of magnetically coupled inductors, preferably constructed in the form of a transformer. Preferably, the first and second windings are magnetically coupled with reduced inter-winding capacitance by axially separating the windings on a common core. The second winding is selectively coupled by a switch to a capacitive load in order to change the inductance of the first winding. The tuning range of the resonant circuit formed by the varactor diode set and the first winding is changed when the capacitive load is coupled. The magnetic coupling between the transformer windings provides DC isolation between the oscillator and the switching circuit. Preferably, a tuning actuator has overlapping ranges of movement for selection of a signal within both the AM and FM frequency bands as the intermediate frequencies for the local oscillator are generated.

Abstract: In accordance with IS-136 standard, an analog wireless signal and a digitally encoded wireless signal can be received by a remote telecommunicating device. The remote device can differentiate between the analog wireless signal and the digitally encoded wireless signal by measuring the average energy of the signal in the portion of the baseband signal that is expected to contain the Supervisory Audio Tone signal, and the portion of the baseband signal that is expected to be outside of the audio band for an analog signal. The average energy of the portion outside of the audio band is subtracted from the average energy of the SAT signal. The difference is compared to a threshold, and based upon the comparison, the characteristic of the received wireless signal, i.e. analog or digital, is determined.