Abstract: A low voltage silicon bipolar RF (radio frequency) receiver front end includes a low noise preamplifier and double-balanced mixer. The receiver incorporates monolithic microstrip transformers for significant improvements in performance compared with silicon broadband designs. Reactive feedback and coupling elements are used in place of resistors to lower the front end noise figure through the reduction of resistor thermal noise, and this also allows both circuits to operate at supply voltages below 2 volts. Circuits fabricated using 0.8 .mu.m Bipolar CMOS technology provide a peak npn transistor transit frequency f.sub.T of 11 GHz. At a supply voltage of 1.9 volts, the measured input third order intercept point is +2.3 dBm with a 10.9 dB single-sideband noise figure. Power dissipated is less than 5 mW. The low noise amplifier input intercept is -3 dBm with a 2.8 dB noise figure and 0.5 dB gain. Power dissipation of the preamplifier is less than 4 mW from a 1.9 V supply.

Abstract: A mixer input circuit for converting a signal from a tuning section of an unbalanced type into a balanced signal and outputting the signal. In the mixer input circuit, an RF signal from an input terminal amplified by an RF amplifier is transmitted to a tuning circuit section employing a distributed constant line. A central conductor of the distributed constant line in the tuning circuit section is electromagnetically combined with a second central conductor, thereby constituting an imbalance-balance conversion section. A middle point of the second central conductor on an output side of the imbalance-balance conversion section is grounded, and a balanced output signal from both ends is transmitted to a mixer, so as to be converted into an IF signal and then to be output from an output terminal. With the present mixer input circuit, imbalance-balance conversion can be carried out without using a transformer, and a reduction in size can be realized due to the absence of deterioration of performance.

Abstract: An amplifier and a portable telephone apparatus using the same in which a resonance circuit is provided for each of different frequencies and bypass capacitors of the ground terminal of a transistor are properly switched according to the different frequencies. Two capacitors connected to each other in series for the parallel resonance circuits to be connected to the output terminal of the amplifying transistor are used for the resonance capacitors for the higher frequency. For the lower frequency, one of the tow capacitors that is on the ground side is used as a bypass capacitor that grounds the ground terminal of the transistor in a high frequency manner, the other capacitor being functioned as a resonance capacitor at that frequency.

Abstract: A radio pager capable of changing the reception frequency thereof, as desired, and having a replaceable crystal oscillator. A reception frequency selecting device selects one of call signals having a plurality of predetermined frequencies which matches the crystal oscillator. A casing is formed with a first opening for allowing the crystal oscillator to be selectively attached to or detached from a printed circuit board, and a second opening for allowing the oscillator to be selectively inserted into or pulled out of the casing.

Abstract: A dumbbell shaped resonator efficiently couples IF signals from short transmission lines to an output transmission line at a radio frequency (RF) mixer's IF output port. The RF mixer uses short transmission lines and terminating resistors to match impedances within the mixer and to minimize the mixer's distortion. The RF mixer, including the dumbbell resonator, is constructed on a printed circuit board and has a low manufacturing cost. Alternatively, the output transmission line is center-tapped to provide a pair of IF signals having opposite phases.

Abstract: A four terminal multiplication circuit capable of mixing up to three input signals. The circuit includes a MOS transistor having gate, source, drain and back-gate terminals. When the circuit is used as an RF mixer or downconverter, an RF signal is provided to the gate terminal and a local oscillator signal is provided to the back-gate terminal. A DC voltage is applied to the source terminal for biasing the transistor and the mixed/downconverted output (IF) signal is obtained from the drain terminal. A single balanced and a double balanced mixer circuit are also disclosed. In the single balanced circuit, two MOS transistors are used; the RF signal is applied to the gate terminals with the positive phase LO component applied to one back-gate terminal and the negative phase local oscillator (LO) component applied to the other back-gate terminal for producing a positive phase and a negative phase IF signal.

Abstract: A radio frequency converter includes a plurality of signal paths for simultaneously processing two RF signals in the same band but with different polarizations, each of which includes a mixer and an oscillator. A common resonator is connected to the frequency control terminal of each of the oscillators and the oscillators work in a push-push configuration.

Abstract: A planar triply-balanced microstrip mixer for microwave and millimeter wave operation includes an RF port, and IF port and an LO port. The mixer is constructed on a single side of a two-sided substrate. The single side of the substrate supports an RF balun network connected to the RF port, an IF balun network connected to the IF port, and an LO balun network connected to the LO port; a pair of crossover diode ring quad circuits arranged in a planar back-to-back configuration; and a planar microstrip feed network connecting the RF, IF, and LO ports to the diode ring quad circuits through the RF, IF and LO balun networks.

Abstract: There is provided a tuner capable of improving reliability thereof with reduced power consumption and reduced heat generation. In the tuner, one wideband amplifier circuit including one transistor constitutes a buffer amplifier. The wideband amplifier circuit is coupled with a first local oscillator circuit in a DC coupling style. With the above-mentioned arrangement, the buffer amplifier is allowed to have a simplified circuit construction and reduce noises. Since the amplifier circuit and the local oscillator circuit are coupled with each other in a DC coupling style, reduced power consumption can be achieved.

Abstract: A time-share mixer circuit and a frequency converter, an I-Q modulator, and an I-Q demodulator. A switching signal drives the time-share mixer circuit to alternate between two output signals. The first output signal represents the output of a mixer having a given signal input and a local oscillator signal with a first phase as its local oscillator input. The second output signal represents the output of the mixer having the same input signal and the local oscillator signal with a second phase that differs from the first phase by 90 degrees as its local oscillator input signal. The frequency converter uses the time-share mixer in combination with a switched output phase shifter that switches in sync with the phase of the local oscillator signal to generate a phase shifted output signal in which the time average of an undesired image signal is substantially reduced compared to time average of the desired signal. The phase shifted output signal is then amplified by a bandpass amplifier.

Abstract: An RF antenna and an associated receiver are proximately located in an integrated antenna/receiver unit thereby eliminating the need for baluns and inter-component cabling characteristic of prior designs. Integration of the receiver with the antenna provides for improved sensitivity as the need for utilizing signal dissipating and noise introducing cables and baluns to transmit the signal received by the antenna to the receiver is eliminated. Direct coupling of the antenna and receiver on a single gallium arsenide integrated circuit maintains balanced impedance from the antenna to the receiver.

Abstract: In a structure adopted for an FM-CW radar, a corner waveguide for connecting each of transmission and reception antennas to a sensor unit is integrated with a sensor unit case. In a waveguide/strip line converter for converting the transmission mode between the waveguide and the strip lines in the circuits of the sensor unit, a ditch is dug in the inner wall of an opening of the waveguide in order to prevent oozing of conductive adhesive. The strip line board is abutted on the inner wall of the waveguide in order to restrict a length of a projecting portion of a line conductor on the strip line board. By employing an oscillator mixer or a multiplier mixer, the circuitry in the sensor unit can be simplified without using lots of expensive millimeter wave devices. Furthermore, power can be utilized effectively even when a switching radar is off, which enables measurement of an absolute speed. Moreover, cost reduction can be achieved.

Abstract: A phase comparator (91) makes a phase comparison between a frequency-divided signal from a frequency divider (98) and a reference oscillation signal from a reference signal oscillator (90). The phase error signal obtained from the comparison is passed through an LPF (92) to yield a frequency control signal, which is applied to a VCO (94). An oscillated signal from is frequency-multiplied by a frequency multiplier (96). The multiplied output oscillation signal SO is frequency-divided by the frequency divider (98) and output to the phase comparator (91). The multiplied output oscillation signal SO is sent out to a receiver circuit (43) and a transmitter circuit (45).

Abstract: A frequency modulator (100) is provided which includes a VCO (200) having a modulation varactor (122) coupled to its output (128). The VCO (200) includes a resonator stage (112) coupled to an amplifier stage comprising a transistor (118). Coupling of the varactor (122) and the resonator stage (112) is provided via the phase collector capacitance (C.mu.) of the transistor (118).

Abstract: A routing YIG-tuned resonator filter integrated with an image-enhanced, double-balanced mixer. The YIG-tuned resonator filter is preferably a four-sphere YIG-tuned preselector which is integrated with a low-loss, fundamentally or harmonically mixed, image-enhanced, double-balanced mixer to provide a high level of dynamic range in a harmonically mixed front end. An input resonator of the preselector in combination with a dual PIN diode switch switches low-frequency input signals (e.g., 0 to 2.9 GHz) to a low-band mixer. For RF input signals (e.g., 2.7 to 26.5 GHz), the four-sphere YIG-tuned preselector is combined with the image-enhanced, double-balanced mixer which incorporates a GaAs monolithic diode bridge integrated circuit. This provides a cost effective front end for a microwave spectrum analyzer.

Abstract: A high frequency receiver detects and downconverts 50-1,000 GHz radio frequency signals using a receiver consisting of a lens and planar antenna, pre-amplifier, mixer, local oscillator, and IF-amplifier. The insulating dielectric lens is used to focus terahertz radio frequency signals onto the thin film antenna. The preamplifier amplifies these faint signals so that they can be downconverted into an intermediate frequency by the mixer and local oscillator. The mixer is a dual port device which provides isolation of the local oscillator and input signal to avoid saturation of the preamplifier. The IF amplifier boosts the amplitude of the downconverted IF signal produced by the mixer.

Abstract: A frequency multiplier and mixer circuit comprises a frequency multiplier circuit composed of a first differential amplifier, which includes a first differential circuit formed of source-coupled first and second FETs having their sources connected in common to a first constant current source and a second differential circuit formed of source-coupled third and fourth FETs having their sources connected in common to a second constant current source. The first and second differential circuits constitute two identical unbalanced source-coupled pairs having the same gate width/length ratio K, input terminals of the pairs being connected in cross-coupled fashion, the output terminals of the pairs being connected in parallel. Gates of the first and third FETs are connected in common to one terminal of a first pair of input terminals for receiving a signal to be frequency-multiplied, and gates of the second and fourth FETs are connected in common to the other terminal of the first pair of input terminals.

Abstract: A quadrant generator for generating a pair of pulse trains maintained in perfect phase quadrant with one another. The quadrature generator includes a feedback control loop for altering the duty cycle of an oscillating signal applied to a master-slave flip-flop pair configured to generate a pair of pulse trains maintained in a relative phase relationship. The feedback control loop controls the duty cycle of the oscillating signal applied to the master-slave flip-flop pair which, in turn, is determinative of the phase relationship between the pulse train pair generated by the master-slave flip-flop pair. When the pulse trains generated by the flip-flop pair are beyond phase quadrature, a control signal generated by the feedback control loop alters the duty cycle of the oscillating signal applied to the flip-flop pair to alter the phase relationship between the pulse trains of the pulse train pair.

Abstract: A structure of a reception frequency converting portion of a multi-band microwave detector, and including a microwave circuit comprises a horn antenna, two-port cavity integrally formed with the horn antenna and having one port communicated with a throat portion of the horn antenna, one-port cavity integrally formed with the two-port cavity and communicated with the other port of the two-port cavity, a mixer diode located at the throat portion of the horn antenna, a first local oscillator arranged within the two-port cavity, and a second local oscillator arranged within the one-port cavity.

Abstract: A wideband transceiver using contiguous overlapping frequency range local oscillators (32, 34) for a high side or a low side local oscillator and an intermediate frequency approaching, within commercialy practical limits, but not exceeding one half of the total limited oscillator frequency range (71).

Abstract: An offset frequency converter for the intermediate frequency (IF) stages of a multi-channel radio frequency (RF) phase/amplitude measurement receiver, particularly useful for measuring the performance characteristics of antennas. The converter allows use of noncoherent transmitter and receiver local oscillator sources which utilize digital frequency synthesizers and enables harmonic mixing to be employed when the tuning resolution of the receiver local oscillator is incremental. The converter samples an incoming first intermediate frequency signal IF.sub.1 in a reference channel, which typically is obtained by mixing an LO source in the receiver with an incoming signal from a reference antenna. The IF.sub.1 sample is then upconverted with an upconversion signal to a higher frequency, filtered, and the downconverted with a downconversion signal to an IF.sub.1 +IF.sub.2 signal offset from the IF.sub.1 sample by a lower second intermediate frequency IF.sub.2. The added frequency offset IF.sub.

Abstract: A down converter device is disclosed which is used in a satellite communication system to convert a microwave signal to an intermediate frequency signal by the use of a standard signal having a frequency range of several to several tens of MHz, and to apply the intermediate frequency signal to a next stage component. The down converter includes a mixer for producing the intermediate frequency signal indicative of a frequency difference between the standard signal and the microwave signal. A separator is provided which includes a first terminal for receiving the intermediate frequency signal, a second terminal for producing and supplying the intermediate frequency signal to the next stage component and for receiving the standard signal from the next stage component, a first filter for separating the standard signal, and a third terminal for producing the standard signal to the mixing means.

Abstract: An RF tank circuit includes a coil with a center tap, the RF tank circuit being for receving an input RF signal, and for providing a balanced mixer circuit by being arranged in one of: a) receiving a local signal through second and third capacitors at first and second coil ends, respectively, with the center tap grounded; and, b) receiving a local signal at the center tap. An impedance is connected between the first and second coil ends of the RF tank circuit, the impedance providing low impendance for a predetermined intermediate frequency signal, and high impedance for a predetermined high frequency signal and a local signal. A bias resistor is connected between a middle connecting point of the impedance and ground.

Abstract: An image suppression harmonic frequency converter capable of operating in any microwave range is described. Frequency conversion is obtained by making use of a local frequency which is half that of a conventional converter. In particular, the radiofrequency reception signal is converted into an intermediate frequency signal with suppression of the converted image band. Similarly, the intermediate frequency signal to be transmitted is converted into a single side band radiofrequency transmission signal. The converter comprises two harmonic mixers, a first inquadrature radiofrequency hybrid coupler, a second in-quadrature intermediate frequency hybrid coupler, two appropriate duplexer filters, two low-pass filters, two matching circuits, and two decoupling circuits.

Abstract: An integrated local oscillator interdigital filter apparatus in a down converter is mounted on the same printed circuit board. The housing of the interdigital filter is cut from sheet metal, with a conductive surface on the printed circuit board as one side. A method for construction of the interdigital filter is also set forth.

Abstract: A mixer incorporating FET's (4,5) as the switching elements includes a resonant circuit connected as a tank circuit of the local oscillator (6) such that the inherence capacitance of the FET's is automatically compensated for. The harmonic recovery technique is also used by the inclusion of rejection filters at the input and output of the system, which rejection filters have reciprocal impedance characteristics, such as short circuit/open circuit or the like.

Abstract: The invention concerns radar detectors which are capable of monitoring at least two frequency bands. A broad band antenna is provided, together with a mixer comprising an anti-parallel pair of diodes, and at least one local oscillator. The local oscillator frequency is mixed with radar frequency from the antenna to produce an intermediate signal which is amplified further down converted detected and fed to signal processing circuitry to actuate an alarm when radar frequency of interest is detected. The most effective mixing with the RF input takes place at twice the local oscillator frequency. By application of direct current bias to the mixer, the most effective mixing with the RF input is changed to occur at the local oscillator frequency. The local oscillator is used to monitor two different radar frequencies by application and non-application of DC bias to the mixer. For multiband detectors, more than one local oscillator may be used.

Abstract: The invention concerns radar detection devices sensitive to signals from various different frequency bands. A broad band antenna is provided, together with a mixer and a plurality of local oscillators. Signals from the local oscillators are mixed one at a time with signals from the antenna, there being one local oscillator signal for each radar frequency or pair of frequencies of interest which may be received by the antenna. Each local oscillator signal is chosen so that when it is mixed with the respective radar frequency signal, an intermediate signal is produced which is the same for all mixtures. This intermediate signal is further down converted and fed to signal processing circuitry to produce an alarm when radar frequencies of interest are detected.

Abstract: The invention concerns a radar detection device--particularly a radar detection for police radar--which is improved with regard to undesirable microwave emissions therefrom. For the X-band and the K-band, for example, two horn antennae are provided, each associated with a local oscillator. A mixer is provided to mix signals from each horn antenna and from its respective local oscillator. Each antenna is made specific to radar signals within its respective band, and precautions are taken to avoid emission of K-band radiation from the larger X-band horn. For example, a bandpass filter for X-band radiation may be used in a feed line branch to the mixer from the X-band horn. The K-band radiation may be fed through in a feed line branch approaching the mixer from an opposed direction.

Abstract: A heterodyne stage of a receiver which includes a conventional mixer circuit and local oscillator circuit further includes a differential amplifier circuit which measures the amplitude of the injection signal generated by the local oscillator circuit and controls it precisely to a desired reference level by adjusting the current bias supply to the local oscillator circuit within a banded range to ensure start-up of the local oscillator upon energization and to protect against loss of injection signal under all operating conditions. The differential amplifier circuit provides for a precise amplitude reference setting and sufficient closed-loop gain for controlling the amplitude of the injection signal with a minimum of error between the measured and reference values.

Abstract: A connecting structure for connecting two oscillator circuits to an amplifier. The oscillator circuits are provided on one surface of a printed circuit board and include two dielectric resonators. The amplifier circuit is provided on the other surface of the printed circuit board for selectively amplifying oscillatory outputs from the oscillator circuits. The dielectric resonators are fixed to a metal plate mounted on the printed circuit board, and the amplifier circuit is located at a position opposite to the metal plate.

Abstract: In a radio receiver which can be switched between at least two waveranges, the coil winding (33) of the oscillator circuit (31) has a further coil winding (36) inductively coupled to it with which a capacitor (37) is arranged in parallel for limiting the waverange comprising the higher frequencies. In the case of reception of the waverange comprising the lower frequencies this capacitor (37) is effectively arranged as a padding capacitor in series with the set of plates (34) of the variable capacitor in the oscillator circuit (31) while simultaneously the further coil winding (36) is effectively arranged in series with the coil winding (33) of the oscillator circuit (31) for the purpose of extending the range and a further capacitor (38) is effectively arranged in parallel with the set of plates (34) of a variable capacitor in the oscillator circuit (31), for the purpose of shifting the waverange of higher frequencies to the waverange of lower frequencies.

Abstract: An antenna coupling system includes separate low-noise receiving amplifier and down converter circuits for amplifying the antenna signal above background noise and for converting it down to frequencies compatible with a suitable receiver, respectively. The system is particularly intended for microwave frequency antennas of the type used to receive satellite signals. The amplifier circuit includes at least one microwave frequency amplifier, such as a GaAs FET, with a low frequency variable feedback circuit connected across it which is arranged to self-tune the amplifier to the antenna input signal strength. The converter circuit is of the image reject single conversion and image recovery type and is arranged to split the amplifier output signal into two parts which are each combined with a local oscillator signal and then re-combined in such a way that unwanted image signals are rejected.

Abstract: Local oscillator power is supplied to an array of single-ended microwave mixers by an offset horn. Each mixer has an integral antenna element.

Abstract: Insertion and conversion losses in a dual frequency microwave mixer circuit are lessened with the improved configuration disclosed herein. The circuit provides inputs for two local oscillator signals, each coupled through a respective bandpass filter. In another embodiment, a pair of notch filters provided near the input reduce leakage from the oscillator inputs to the signal input.

Abstract: A frequency conversion apparatus for converting a high frequency signal into an intermediate frequency signal includes a mixer section for mixing a high frequency signal with a local oscillator signal so as to obtain an intermediate frequency signal, and an amplifier connected to the mixer section via a high frequency stopping circuit for supplying a constant direct current to the mixer section as a constant current source. A current flowing in the mixer section when the local oscillator signal is applied is kept substantially equal to a direct current flowing in the mixer section when no local oscillator signal is applied thereto. The amplifier is used for amplifying either the high frequency signal or the intermediate frequency signal, or both signals at the same time.

Abstract: A local oscillator null circuit and method for use in tuning a wideband, heterodyne receiver relatively close to zero frequency without experiencing excessive feedthrough from a local oscillator to an associated IF stage in the receiver. The local oscillator is connected to circuit means for generating a derivative signal proportional to the local oscillator signal and shifted in phase with respect thereto by a desired amount determined by the phase difference between the local oscillator signal and the signal in the mixer output spectrum which is at the local oscillator frequency. The null circuit combines the derivative signal with the mixer output signal proportionally to produce a null at the local oscillator frequency.

Abstract: A prescaler input circuit for a frequency converter unit uses a strip line type of directional coupler to isolate the prescaler unit from the frequency converter unit, eliminate beat interference and erroneous frequency dividing operation, and provide a simple and economical structure. The coupler has the prescaler input line inductively coupled to a local oscillator injection element and grounded through a resistor. An earth line is arranged in proximity to the injection lead to provide impedance matching for the coupler.

Abstract: A 3 dB quadrature coupler is connected to an RF input terminal and an LO input terminal, and its outputs are connected to first and second antiphase power dividers. The outputs of the first and second antiphase power dividers are individually connected to the gates of four field effect transistors (FET's). The drains of two of the FET's are connected together and to a low pass filter, and the drains of the other two FET's are connected together and to a second low pass filter. The outputs of the filters are connected to the two inputs of a differential amplifier, and the IF signal is taken at the output of the differential amplifier.

Abstract: A first 3 dB quadrature coupler is connected to an RF input terminal and its outputs are connected to first and second antiphase power dividers. The outputs of the first and second antiphase power dividers are individually connected to the first gate of four dual-gate field effect transistors (FET's). A second 3 dB quadrature coupler is connected to an LO input terminal and its outputs are connected to third and fourth antiphase power dividers. The outputs of the third and fourth antiphase power dividers are individually connected to the second gates of the four FET's. The drains of two of the FET's are connected together and to a low pass filter, and the drains of the other two FET's are connected together and to a second low pass filter. The outputs of the filters are connected to the two inputs of a differential amplifier, and the IF signal is taken at the output of the differential amplifier.

Abstract: RF-tuning device comprising a switching mixer stage (M) and a tuning oscillator (O) coupled thereto. According to the invention, so as to reduce the noise contribution of the mixer stage (M) without increasing the oscillator radiation, the slew rate of the oscillator switching signal applied to the mixer stage (M) is increased by connecting bistable trigger circuit between the tuning oscillator and the mixing stage. Under the control of the tuning oscillator, the bistable trigger circuit generates a substantially square-wave output signal.

Abstract: In a VHF tuner, feedback capacitance between the emitter of a local oscillating transistor and the ground in a local oscillator is changed at the low band receiving state and high band receiving state by controlling a switching diode connected in series to a capacitor for feedback capacitance and, a mixer is installed to mix the output of the local oscillator and high frequency input. For an improved mixer biasing circuit, the switching diode in series connection to the capacitor for feedback capacitance is connected to one terminal of a mixing FET in the mixer, and changing of the feedback capacitance in the local oscillator is accompanied by changing of working current of the mixing FET in the local oscillator.

Abstract: An amplifier for use with a local oscillator in a frequency converter including a mixer for converting a number of channel frequencies received into a certain band of intermediate frequencies, comprises a circuit for amplifying an oscillation signal from the local oscillator and supplying an amplified signal to the mixer through an output terminal thereof, and a trap circuit composed of distributed constant elements for suppressing the certain range of intermediate frequencies. The distributed constant elements include a first microstrip line connected in series to the output terminal, a second microstrip line connected in series with the first microstrip line, and a third microstrip line connected in parallel to the second microstrip line. The second microstrip line serves as an open stub, and the third microstrip line as a short stub.

Abstract: A receiver including an FET frequency mixer is disclosed. A local oscillator generates a local oscillator signal which is applied to a first amplifier whose gain is varied as a function of a control signal applied thereto. The output of the first amplifier is applied to a first gate electrode of the FET frequency mixer. A high-frequency signal received by the receiver is applied to a second amplifier whose gain is also controlled by the control signal. The output of the second amplifier is applied to a second gate electrode of the FET frequency mixer. The control signal is generated as a function of the output of the FET mixer.

Abstract: A microwave oscillator and a combination microwave oscillator/single balanced mixer for a satellite television receiver includes a cylindrical dielectric resonator located on one side of a ground plane formed by a conductive foil on a substrate with microstrip transmission lines formed by foil patterns on the opposite side of said substrate. A gallium arsenide FET is disposed in a hole through said substrate with its source electrode connected to the ground plane and its drain and gate electrodes coupled to first and second transmission line strips, portions of which are following the contours of said dielectric resonator. Two sets of coupling slots are formed in the ground plane for permitting magnetic coupling between the dielectric resonator and the opposite transmission line strips. In one embodiment an additional coupling slot in the ground plane couples the dielectric resonator to an output transmission line strip.

Abstract: An improved active balanced mixer for developing an IF signal by combining an RF signal and a local oscillator signal while providing high conversion gain. The mixer utilizes a series resonant circuit resonant at the IF frequency to reduce degenerative feedback effects at the IF frequency, thereby increasing conversion gain. Circuit is particularly adapted for a receiver in which the received RF signal is relatively close to the receivers IF frequency.

Abstract: A circuit arrangement for converting high frequencies to intermediate frequencies by mixing with a heterodyne frequency, wherein the high frequency signal input is connected to the signal output of the circuit arrangement via the primary winding of a polarity reversing transformer which is controlled such that the high frequency input signal appears at the signal output, alternatingly once directly and once with reversed polarity in the rhythm of the heterodyne frequency, and thus the high frequency signal is mixed with the heterodyne frequency. The polarity reversal is controlled by alternatingly opening and short-circuiting the secondary winding of the polarity reversing transformer in push-pull with the center tap of the primary winding by means of electronic switching circuits responsive to the heterodyne frequency.

Abstract: A UHF television receiver tuner comprises a varactor tuned circuit coupled to an input electrode of a field effect transistor mixer through a serially connected RF coupling capacitor. A local oscillator signal is coupled to the input electrode of the field effect transistor mixer through an inductive loop whose inductance value is chosen such that proper impedance matching over the UHF band is achieved.

Abstract: A frequency converter has first, second and third terminals which receive a first signal having a first frequency band, a local oscillation signal, and a second signal having a second frequency band. The first signal and the local oscillation signal are mixed to generate the second signal. A first branching circuit is connected between the second terminal and the frequency mixer, for branching part of the local oscillation signal. A first part of the branched local oscillation signal, which is supplied from the first branching circuit, and a first leaked local oscillation signal are applied from the frequency mixer to the first terminal. The phase and amplitude of the first branched local oscillation signal are adjusted so that the first branched local oscillation signal and the first leaked local oscillation signal have equal amplitude and are reversed in phase to cancel each other.

Abstract: A frequency converter comprises a frequency converting circuit, and filters which are input and output functional with respect to the frequency converting circuit for passing input and output frequency waves respectively and which have different passing frequency bands. A single terminal is provided for the frequency converter, through which reception of the input frequency wave to the input functional filter and delivery of the output frequency wave from the output functional filter are effected.