Abstract: A transponder receiver for detecting different radio frequency (RF) interrogation mode signals having relatively wide and narrow bandwidths about a common RF center or carrier frequency. A front end stage of the receiver has a preselector with a wide band RF filter for passing both of the wide and the narrow bandwidth interrogation mode signals about the RF center frequency, and a mixer for converting signals from the preselector to frequencies within an intermediate frequency (IF) band. A first IF channel has a narrow band IF filter with a pass band sufficiently wide to pass first IF signals corresponding to the narrow bandwidth interrogation mode signals, but to reject signals corresponding to undesired interfering signals at frequencies near the narrow bandwidth interrogation mode signals. A second IF channel has a wide band IF filter with a pass band sufficiently wide to pass second IF signals corresponding to the desired wide bandwidth interrogation mode signals.

Abstract: A wireless communication device comprises a plurality of receive signal paths, each of the receive signal paths is configured to receive signals in a certain frequency bandwidth. The communication device also comprises an amplifier coupled with each of the plurality of receive signal paths. The amplifier is configured to amplify the receive signals associated with each of the plurality of receive signal paths.

Abstract: An FM broadcast transmitter transmits a broadcast signal having a carrier at a broadcast frequency and sidebands, able to be transmitted at full power, within a transmission band-width around the carrier. It includes a source of a modulated FM stereo signal having a carrier at the broadcast frequency and having sidebands with a bandwidth less than the transmission bandwidth representing a stereo signal. It also includes a source of a modulated IBOC signal, having carrier pulses spaced relative to each other to represent the IBOC digital data signal encoded as a variable pulse width encoded signal, and a bandwidth within the transmission bandwidth not overlapping the FM stereo signal sidebands. A signal combiner combines the modulated FM stereo signal and the modulated IBOC signal to form the broadcast signal.

Abstract: The present invention relates to a high frequency composite component used in a front end section for processing a high frequency signal between a transceiving section and an antenna in a high frequency circuit of a mobile communication device.

Abstract: A dual mode tuner/receiver is disclosed in which both analog and digital signals can be received and processed. A low pass filter allows all channels below a selected frequency enter the circuit. A precisely controlled dual conversion circuit creates an intermediate frequency (IF) signal. An automatic carrier detection circuit monitors the IF signal and determines whether the signal is of analog or digital format and intermediate frequency filters are adjusted based upon the type of signal detected. A coherent oscillator circuit generates in-phase and quadrature reference signals that are used by video and audio detectors for further processing of the IF signal. In-phase and quadrature outputs are provided for digital signals and composite video and audio outputs are provided for analog signals.

Abstract: A system for receiving a transmitted signal is provided. The system includes a first receiver that can receive the transmitted signal and decode the transmitted signal according to a first demodulation format, such as a CDMA or PCS format. A second receiver, such as an FM demodulator, is connected to the first receiver at a suitable location, such as after initial signal amplification and processing has been completed. The second receiver can decode the transmitted signal according to a second demodulation format, such as AMPS.

Abstract: This invention provides a method for reducing FM interference in an in-band on-channel digital audio broadcasting system. The method includes the steps of receiving a composite signal including a signal of interest and an interfering signal and normalizing the composite signal to produce a normalized composite signal. The composite signal is then multiplied by the complex conjugate of the normalized composite signal to produce a real signal. Then the real signal is filtered and the resulting filtered signal is multiplied by the normalized composite signal to produce an output signal. The adverse effects of the interfering signal in the output signal are reduced with respect to the magnitude of the signal of interest reducing FM interference in an in-band on-channel digital audio broadcasting system, thereby making it easier to detect the signal of interest.

Abstract: Disclosed is a method and apparatus of transmit diversity that is backward compatible and does not significantly degrade performance in additive white guassan noise (AWGN) conditions using a transmission architecture that incorporates a form of phase sweep transmit diversity (PSTD) referred to herein as biased PSTD. Biased PSTD involves transmitting a signal and a frequency swept version of the same signal over diversity antennas at different power levels. By transmitting the two signals at different power levels, the depths of nulls normally seen in AWGN conditions when PSTD is utilized is reduced and performance degradation in AWGN conditions is mitigated.

Abstract: A system for combining AM and FM transmissions. In-band, on-channel, FM Digital Audio Broadcast (IBOC FM-DAB) allows simultaneous transmission of DAB and FM over existing FM allocations without interfering with conventional analog FM signals. The utility of existing FM spectrum allocations is therefore enhanced.

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: 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: A method for sending data from a transmit site to a receive site which includes dividing a transmit data stream having a first bit rate into multiple data streams with each of the multiple data streams having a bit rate which is lower than the first bit rate, transmitting each of the multiple data streams over a plurality of RF channels and recombining the multiple data streams at the receive site to provide a receive data stream having a bit rate equal to the first bit rate.

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: The present invention relates to an arrangement (1) and a method in a receiver in a multi-mode mobile radio (m), wherein the intention is to design the receiver so that it uses the same hardware to process several different channel bandwidths corresponding to the different networks used by the radio (m). This is done by changing a sampling frequency (fs) which controls a digital filter unit (25) situated in the digital part of the receiver. The changing of the sampling frequency (fs) results in that the bandwidth of the digital filter unit (25) is scaled accordingly, wherein the desired channel bandwidth at baseband of the radio network (GSM1900, AMPS) to be used by the radio (m) is selected in the digital filter unit (25). As a complement, the digital filter unit (25) can be implemented with a programmable function, where a change of parameters and/or filter structure inside the digital filter unit (25) can be used to adjust the filter bandwidth.

Abstract: An RF transmitter, such as a radar transmitter or a communications amplifier, is provided that includes a plurality of RF power tube sections each sharing a common collector. The RF tube sections may comprise Klystron tubes, TWT tubes or other RF power tubes known in the art. A common modulator is also typically provided to modulate electron beams produced in each of the plurality of tube sections. The RF transmitter according to the present invention is considerably lighter and smaller relative to known multi-band RF transmitter structures that employ separate collectors and modulators. An associated RF amplification method that employs a common collector is also provided.

Abstract: Apparatus, and an associated method, for radio receiver circuitry operable in multi-modes to receive signals generated during operation of a multiple number of radio communication systems. The receiver circuitry is divided into receive chain portions which are selectably utilized depending upon which of the multiple number of the radio communication systems in which communications are to be effectuated. Selected combinations of the receive chain portions are formed, depending upon which of the modes in which the receiver circuitry is to be operable. Different combinations of the receive chain portions permit sharing of receive chain portions thereby to reduce the required number of circuit elements to form the multi-mode receiver circuitry. In one implementation, the radio receiver circuitry forms the receive portion of a dual-band, tri-mode mobile station operable in a selected one of three different cellular communication systems.

Abstract: This invention provides a method for reducing FM interference in an in-band on-channel digital audio broadcasting system. The method includes the steps of receiving a composite signal including a signal of interest and an interfering signal and normalizing the composite signal to produce a normalized composite signal. The composite signal is then multiplied by the complex conjugate of the normalized composite signal to produce a real signal. Then the real signal is filtered and the resulting filtered signal is multiplied by the normalized composite signal to produce an output signal. The adverse effects of the interfering signal in the output signal are reduced with respect to the magnitude of the signal of interest reducing FM interference in an in-band on-channel digital audio broadcasting system, thereby making it easier to detect the signal of interest.

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 mode radio apparatus has an integrated filtering part (51) which includes an antenna port (51a) for connection to an antenna (21), at least one port (51b, 51c, 51d) for connection to each of the system-specific radio-frequency parts (54, 55) of the dual mode radio apparatus and filtering means for directing the propagation of signals between ports on the basis of the signal frequency. The integrated filtering part replaces earlier separate filters and their impedance matching circuits as well as some of the required radio-frequency switches.

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 multiband mobile unit communication apparatus comprises: antennas for receiving plural radio wave SIGs respectively transmitted from plural mobile unit communication systems, the plurality of radio wave SIGs having different carrier frequencies respectively; independent CKTs for generating IF SIGs from the radio wave SIGs from the antennas respectively; and a common CKT including a switch according to a mode SIG, a quadrature demodulation CKT for directly converting the IF SIG from the switch into I and Q baseband SIGs, and a decoding CKT for outputting a decoding result from said I and Q baseband SIGs. In accordance with the mode SIG, power is selectively supplied to the independent CKTs, a switchable FRQ-divider may be provided to FRQ-dividing a LO SIG for the quadrature demodulation CKT, a switchable tuning CKT may be provided to the variable gain amplifying CKT to provide a switchable tuning FRQ, switchable low-pass filters may be provided to switchably low-pass-filter the I and Q baseband SIGs.

Abstract: The present invention relates to a multiple band receiver comprised in a mobile terminal. The receiver is able to receive radio signals in an upper frequency band (FB.sub.U) and a lower frequency band (FB.sub.L). The multiple band receiver comprises an antenna (ANT), a converting receiver part (R1), a heterodyne receiver part (R2) and a voltage controlled oscillator (VCO). The voltage controlled oscillator generates local oscillator frequencies (f.sub.LO) substantially equal to the frequency shift between the two frequency bands. Radio signals (f.sub.RF) in the upper frequency band (FB.sub.U) are converted in the converting receiver part (R1) to substantially the lower frequency band (FB.sub.L) by mixing with a local oscillator frequency (f.sub.LO). The converted signal is mixed in the heterodyne receiver part (R2) with the same local oscillator frequency (f.sub.LO) thus generating the same first intermediate frequency (f.sub.IF1) as for signals in the upper frequency band.

Abstract: In a radio communication system (100), enhanced communication capability is provided while maintaining standard channel modulation compatibility. At a transmitter (110, 200, 600), a first information signal is generated from data according to a predefined standard modulation scheme (212, 613). A second information signal is generated from data that provides supplemental information to the standard modulated data (213, 616). For transmission, the first and second information signals are combined into a composite signal (214, 619) that represents the first information signal when interpreted according to the predefined standard modulation scheme.

Abstract: A multiband mobile unit communication apparatus is disclosed which comprises: an antenna for receiving 1st and 2nd bands of radio wave SIGs including quadrature modulation SIGs; a 1st LO CKT for generating a 1st LO SIG; 1st and 2nd receiving CKTs for generating 1st and 2nd IF SIGs from the 1st and 2nd bands of radio wave SIGs using the 1st LO SIG respectively; a switching CKT responsive to a switching control SIG indicative of 1st and 2nd modes for outputting the 1st IF SIG in the 1st mode and outputting the 2nd IF SIG in the 2nd mode; a 2nd LO CKT for generating 2nd and 3rd LO SIGs in the 1st and 2nd modes respectively; and a quadrature demodulation CKT for demodulating and outputting quadrature SIGs from an output from the switching CKT using the 2nd and third LO SIGs in the 1st and 2nd modes respectively.

Abstract: A system for combining AM and FM transmissions. In-band, On-channel, FM Digital Audio Broadcast (IBOC FM-DAB) allows simultaneous transmission of DAB and FM over existing FM allocations without interfering with conventional analog FM signals. The utility of existing FM spectrum allocations is therefore enhanced.

Abstract: An integrated RF avionics system having a common IF interface for diverse functions, such as radar, electronic waveform(EW) and communications/navigation/identification(CNI). The interface uses a segmented band of IF frequencies which are subdivided into two or more individual band segments separated by a guard band segment. The lower frequency band segment comprises a narrow band segment which is assigned to radar functions while the other or upper band segment comprises a wideband segment assigned to other functions such as EW and CNI functions. The guard band is not used for signal transmission, but is left unused to permit bandpass filters to reject signals in the adjacent unwanted segment, thus achieving frequency separation across the IF band while allowing the use of common hardware. The total IF range is sufficiently wide that radar, EW and CNI signals can be separated from each other with practical filters while being routed through a common IF switch network.

Abstract: A data-in-voice modem is disclosed using charge coupled devices. Unique features include: (1) Baseband-to-IF upconversion to enable CCD-based demod/processing; (2) All analog (no analog-to-digital A/D required); option for post-CCD A/D; (3) Additional on-chip functions; (4) Stand-alone, CCD-based high-rate modem over telephone lines; and (5) CCD-based cable-tv/multimedia processing, via baseband-to-IF upconversion, followed by IF-sampled CCD processing.

Abstract: A high frequency power amplifier is implemented by a GaAs FET and is supplied with a positive and a negative power supply. The amplifier amplifies the power of an input signal and delivers the amplified signal to a high frequency switch. The high frequency switch is supplied switch control voltages in the form of the positive and negative voltages. Since the switch control voltages are implemented as the positive and negative voltages, a great difference in level between the switch control voltages is achievable which improves insertion loss. While the high frequency switch may also be implemented by GaAs FETs, the insertion loss will be further reduced if the negative voltage is applied to the high frequency switch only during transmission. In this case, current consumption will also be reduced if the generation of the negative voltage is controlled at the negative voltage source side.

Abstract: A selectable demodulator (32) operates in the phase domain to implement a coherent demodulation path (40) and a differentially coherent demodulation path (42). The coherent path (40) includes a differential encoder circuit (46) to produce coherently demodulated differential data. Magnitude converters (62, 62') convert phase errors in each path into magnitude values. A comparison circuit (66) compares magnitude values from the two paths (40, 42) and selects the path encountering the least phase error. A selection circuit (60) provides data codes demodulated in accordance with the selection.

Abstract: A vehicle radio receiver circuit includes two antennas for mounting on the vehicle. The antennas are significantly less than one quarter of a wavelength in length at the desired frequency of operation, and the outputs of the antenna elements are coupled to two inputs of an FM circuit and two inputs of an AM circuit, which includes summing circuitry. The FM circuit has an FM output for providing a received FM signal, and the AM circuit has an output for providing an AM signal that includes a sum of signals derived from the outputs of the antennas.

Abstract: A system for combining AM and FM transmissions. In-band, On-channel, FM Digital Audio Broadcast (IBOC FM-DAB) allows simultaneous transmission of DAB and FM over existing FM allocations without interfering with conventional analog FM signals. The utility of existing FM spectrum allocations is therefore enhanced.

Abstract: A broadband tuning circuit adapted for receiving both BS and CS broadcasting signals. The circuit includes an input circuit for receiving RF signals which associated with the BS and CS broadcasting signals, respectively, a splitter for splitting the RF signal to a low RF signal and a high RF signal, an oscillator for generating a local frequency signal, a first mixer for frequency converting the low RF signal to a first IF signal in the up-heterodyne fashion using the local frequency signal, a second mixer for frequency converting the high RF signal to a second IF signal in the down-heterodyne fashion using the local frequency signal, a selector for selecting either the first or the second IF signal and a demodulator for demodulating the information from the selected IF signal.

Abstract: In an active circuit which separates and amplifies signals received via an antenna (A) into a higher-frequency FM band and a lower-frequency FM band, weakening of the FM signals by the AM-band amplifier is avoided by adding, to the previously known circuit which has first, second, and third capacitors (C1, C2, C3), a third inductance (L3) between the second (C2) and third (C3) capacitors, and by removing any serial inductance from the adaptor or matching circuit (AP) at the input of the FM amplifier stage (UKW).

Abstract: In a system where 2-level modulation and 4-level modulation of communication signals exist, an apparatus (107) demodulates either modulation scheme by demodulating (301) a received signal under the presumption that it is a 4-level signal, and if the received signal is detected (309) to be a 2-level signal, the signal is then demodulated (319) as a 2-level signal.

Abstract: A variable frequency RF passband filter is aligned or calibrated to maximize the sensitivity of a radio receiver using reference frequencies obtained using a fixed frequency oscillator present in a different band tuning section of a multiband receiver. The intermediate frequencies of the various band sections of the multiband receiver are selected whereby a fixed frequency source in one band corresponds to an intermediate frequency employed in the band for which the tunable RF filter is being aligned.

Abstract: Upon transmission, when the digital transmission mode is set, an analog audio signal is A/D converted, the digital audio signal is coded, a first carrier is modulated by the coded signal and multiplied by a first multiplier, and the multiplied signal is sent to an orthogonal modulating and D/A converting circuit. When the analog transmission mode is set, a second carrier is modulated by the digital audio signal and multiplied by a second multiplier, and the multiplied signal is sent to the orthogonal modulating and D/A converting circuit. A signal of a frequency which is equal in both of the digital transmission mode and the analog transmission mode is given to the orthogonal modulating and D/A converting circuit. Upon reception, when the digital transmission mode is set, an output of an A/D converting and orthogonal demodulating circuit is frequency divided by a first frequency divider and demodulated and decoded.

Abstract: A received modulated information signal is converted to an intermediate frequency (IF) signal from which modulating information may be recovered by supplying the modulated information signal to two mixers supplied with local oscillating signals of equal frequency but phase shifted with respect to each other. Output signals produced by the mixers are supplied through phase shift circuits which impart predetermined phase shifts thereto such that image signal components present in respective ones of the mixer output signals are phase shifted to be out-of-phase with each other. The phase shifted mixer output signals are combined, whereby the out-of-phase image signal components are substantially cancelled. A filter tuned to the IF frequency is coupled to the output of the combining circuit to pass the mixer output signals having frequencies within a predetermined range of the IF frequency.

Abstract: The invention relates to a television receiving tuner for receiving television signals of VHF band/UHF band, a CATV signal, and a satellite television broadcasting signal. As a circuit for receiving the television signals of the VHF band/UHF band and the CATV signal as a first input signal, there is provided a double super type tuner of the up/down converter system including a first local oscillator (6) and a first mixer (5) which construct an up converter and a second local oscillator (10) and a second mixer (9) which construct a down converter. When the satellite television broadcasting signal as a second input signal is received, the first local oscillator (6) and the first mixer (5) in the up converter section are switched by switching circuits (12, 13) and used as a down converter.

Abstract: Methods for detection or, or equivalently, demodulation of phase-and-amplitude-shift-keyed communication signals that may be received via multipath propagation or dispersion in a noisy channel are disclosed. The signal format has a block structure with a fixed pattern preceding and following the data portion of each block. Implementation is accomplished in real-time by obtaining samples of the complex-envelope of the received waveform, processing at the symbol rate mainly in the frequency domain, then returning to the time domain with a coagulated signal where ordinary detection of the symbols is completed according to the modulation in use. The signal format and computation in the frequency domain permit the estimation of the multipath-structure of the channel, which in turn permits the estimation of the data using a reasonable amount of processing. Performance of the basic method is substantially improved by generating a metric and searching for alterations of the data that reduce the metric.

Abstract: A multi-band receiver for receiving broadcast signals divided by frequencies into an FM group and a TV group, the TV group including at least two different frequency ranges separated by a substantial frequency gap. The receiver includes a band selector for selecting a desired frequency group from the two group, a tuning controller for selecting a desired broadcast frequency within the desired group from a predetermined tuning band, an oscillator for separating signals of the desired frequency from the received broadcast signals and converting the separated signals into audio signals and a frequency adjuster responsive to the band selector and the tuning controller for automatically adjusting the oscillation frequency of the oscillator when the TV group has been selected for substantially removing the frequency gap from the predetermined tuning band.

Abstract: A radio receiver has an IF amplifier whose output is connected to an AM demodulator and an FM demodulator. The noise level at the output of the FM demodulator is measured and, when it exceeds a predetermined threshold level, the audio output stage of the receiver is disconnected from the circuit. Noise generated when amplitude modulated signals with a high degree of modulation are received may cause unwanted disconnection of the output circuit. This is prevented by a circuit connected to the output of the AM demodulator which detects negative peaks of the modulation signal which exceed a negative threshold. The integrated peak signals form a correction signal which prevents disconnection of the output stage.

Abstract: An automatic signal optimizing interface for connection between the antenna of an automobile radio receiver and the receiver itself processes the RF signal received by the antenna and provides an improved output signal to the automobile receiver which is optimized for distortion free reception. The output signal is limited to the desired frequency band to eliminate interfering signals, and is maintained within the optimum dynamic range of the receiver, even under reception conditions in which the received antenna signal itself is excessively high or undesirably low. The interface therefore permits superior performance by the radio receiver by optimizing the signal supplied to the radio and by preventing intermodulation distortion which otherwise commonly results from overloading of the front end of the radio receiver by excessively strong received signals.

Abstract: A receiving reproducing system for an automotive radio detects the surrounding noise level other than the output sound thereof, in the sound field extending in the passenger compartment of an automobile, and the level which is dependent upon the received signal level of an antenna. The receiving reproducing system partly controls its output sound volume proportionally in accordance with the surrounding noise level and partly lowers its output sound volume in dependence upon the reduction in the received signal level. Even under the circumstances where the surrounding noise level is high and where the received signal level is low, the sound volume of the output sound containing many noises can be prevented from being raised.

Abstract: A semiconductor chip contains a multi-channel signal-processing circuit for processing signals in different frequency bands (e.g., an AM and an FM receiver). An inductor is coupled via an external terminal on a package for the semiconductor chip to a first signal-processing circuit. A circuit detects when a connection is made between the inductor and a power supply terminal contained in the semiconductor chip. When the inductor is connected to the power supply terminals, the first signal-processing circuit is activated, while the second signal-processing circuit is deactivated. When the inductor is disconnected from the power supply terminal, the second signal-processing circuit is activated, while the first signal-processing circuit is deactivated. The circuit for detecting a connection between the inductor and the power supply terminal is either a circuit for detecting a potential change or a circuit for detecting an oscillating signal.

Abstract: An integrated circuit, when operated from a simple single-pole-double throw switch, performs all of the functions required to switch modes in an FM-AM radio. The radio frequency circuits are switched directly and, in response to the AM oscillator circuit state, electronic switching is employed to switch the FM limiter, AM mixer, and audio amplifier. In the FM mode, the audio amplifier has high fidelity wide band response. In the AM mode, the audio amplifier is switched to operate with a reduced bandwidth. Thus, the audio amplifier does not produce signal components that can be picked up by the AM antenna, where they are interpreted as noise.

Abstract: A detector circuit for detecting AM and FM signals adapted particularly for integrated circuit fabrication which has a circuit configuration that provides highly stable operating characteristics for both AM and FM operation and is responsive to an increased dynamic range of AM signals. The circuit is uniquely designed to exhibit minimal bias and output voltage variations in the presence of unavoidable IC process changes from one circuit to another and ambient temperature changes, by employing an arrangement of circuit components that readily compensate for such changes.