Abstract: A radio using non-simultaneous frequency diversity includes: an antenna, a radio frequency module coupled to the antenna such that the radio frequency module is operable to transmit or receive radio frequency signals using the antenna, and a baseband module coupled to the radio frequency module. The baseband module is operable to transmit or receive signals through the radio frequency module, such that signals transmitted or received by the radio employ non-simultaneous frequency diversity. A method for transmitting information using non-simultaneous frequency diversity includes: identifying information to be transmitted, transmitting the identified information on a first channel, and after a predetermined amount of time, transmitting the identified information on a second channel.

Abstract: An apparatus and method for calibrating a non-crystal oscillator in a transceiver unit using a crystal-oscillator includes the step of establishing a time base based upon oscillations of the crystal oscillator. A comparison of the number of oscillations for the non-crystal oscillator and the crystal oscillator is made during a known time period is made. An adjustment is determined based upon the established time base and the compared number of oscillations. The transceiving of the transceiver unit is then controlled based upon this adjustment.

Abstract: A first receiver frequency reference is passively coupled to a second receiver by tapping a signal directly from the resonant element, such as a crystal, of an oscillator in the first receiver to drive the input of the second receiver. The sinusoidal signal from the resonant element is relatively free of harmonics and minimizes interference that could be caused by harmonics of a square wave signal coupling or an amplified signal. The oscillator of each receiver can be selectively enabled or disabled to allow the receiver to either generate or receive the frequency reference. This technique of coupling can be used to couple a frequency reference signal between integrated circuit receivers.

Abstract: A modem generates a new RSSI threshold value in response to a flag signal representing the quality of the threshold value indicated by the result of error detection supplied from one monitor, and supplies the generated threshold value to another monitor. The RSSI threshold value set in the other monitor is rendered variable, the modem thus being able to operate with the threshold value converging precisely in a short time.

Abstract: A simplified architecture is disclosed for ADC conversion of received in-phase I and quadrature Q signals. Circuit area is substantially reduced by sharing a single ADC to convert both signals, switching the ADC input alternately between the i and q signals. In an embodiment, the ADC is clocked at an increased sample rate, and the digital output signals are aligned to compensate for the phase difference resulting from the implementation of a single ADC. Aligning includes delaying one of the digital signals, and interpolating the other one of the digital signals in a low pass filter so as to compensate for the phase difference introduced by the sampling during the first and second time intervals. The first and second time intervals are equal to a predetermined ADC sample period corresponding to a sample clock cycle. Delaying the first digital signal includes a delay of 1/2 clock cycle.

Abstract: The present invention eliminates the need for an anti-aliasing filter in a receiver that employs an analog-to-digital converter. By maintaining a predetermined relationship between a local oscillator frequency and the sampling frequency of the analog-to-digital converter, aliasing that would normally occur in the desired pass band is avoided. More specifically, the frequency of the periodic signal provided to the mixer is an integer multiple of half the sampling rate of the analog-to-digital converter. In a preferred, non-limiting example embodiment, the sampling rate of the analog-to-digital converter FADC and the frequency of the local oscillator FLO are related by the following: FLO=n*FADC/2, where n is any positive integer.

Abstract: In a heterodyne receiver, the effect of an image interference signal that occurs in a case where a low intermediate frequency is used is alleviated. Circuits (12I), (12Q), (13I), (13Q), and (14) are provided to switch a heterodyne system between an upper heterodyne system and a lower heterodyne system. The switching circuits (12I) to (14) switch the heterodyne system into one of the upper heterodyne system and the lower heterodyne system with less image interference on the basis of each reception frequency.

Abstract: Mobile terminal implementing a ranging signal receiver and method. Means are provided to incorporate ranging signal reception capability into a mobile terminal (such as a UMTS terminal) notwithstanding the fact that the ranging signal has a bandwidth that is wider than the bandpass of filtering for native signals within the terminal. A ranging signal receiving subsystem receives broadband signals that comprise synchronization bursts, which are equally spaced in time, such as from digital television stations. A common filter will have a bandpass that it is smaller than the bandwidth of the ranging signals. However, the correlation subsystem of the mobile terminal enables recovery of synchronization bursts by correlating the ranging signal with a known sequence that has been predistorted to account for the bandpass of the common filter.

Abstract: Dispersing directions of oscillation frequency variable ranges of all voltage controlled oscillators provided in an integrated circuit are uniformed, and not only a range covering a frequency regardless of whether a dispersion occurs or not, but also a range covering the frequency only in a case where the dispersion occurs is used as the frequency variable range of the voltage controlled oscillator, and the frequency variable ranges of the voltage controlled oscillators are set so as to be successive with respect to each other, so that a small number of voltage controlled oscillators can cover a wide frequency variable range. Thus, the integrated circuit having voltage controlled oscillators therein is miniaturized.

Abstract: A full-duplex transceiver using a method immunizing itself against self-jamming. The transceiver includes a receiver and a transmitter. The receiver includes a frequency immunization converter and a high pass IF filter. The transmitter transmits a TX signal. The receiver receives an RX signal and simultaneously receives a portion of the power of the TX signal as an undesired TX jamming signal. The frequency immunization converter uses the center frequency of the TX signal for downconverting the RX signal to an IF signal and simultaneously downconverting the TX jamming signal to near zero frequency. The high pass IF filter passes the IF signal and blocks the signal at near zero frequency. As a consequence of the downconversion using the TX frequency, a second LO frequency is controlled for avoiding image frequencies.

Abstract: An exemplary embodiment of the present invention described and shown in the specification and drawings is a transceiver with a receiver, a transmitter, a local oscillator (LO) generator, a controller, and a self-testing unit. All of these components can be packaged for integration into a single IC including components such as filters and inductors. The controller for adaptive programming and calibration of the receiver, transmitter and LO generator. The self-testing unit generates is used to determine the gain, frequency characteristics, selectivity, noise floor, and distortion behavior of the receiver, transmitter and LO generator. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or the meaning of the claims.

Abstract: A wireless communications device includes an antenna that receives a first signal at a first frequency and a second signal at a second frequency and converts the first and second signals into a composite signal. A first oscillator outputs a first oscillator signal at a first frequency and a second oscillator outputs a second oscillator signal at a second frequency. A demodulator receives the composite signal and the first and second oscillator signals. The oscillator signals are selected so that the demodulator generates a low frequency signal with components of the first and second signals occupying a common frequency band. The wireless communications device allows executing a “Soft Handoff” even when the first and second frequencies are different.

Abstract: A power supply circuit of a low noise block converter (LNB) includes a plurality of output voltage regulators. A first output voltage regulator, a local oscillator circuit, a second output voltage regulator, and an LNA are connected in series in a direction in which a power supply current flows. Therefore, a voltage adjustment width of the output voltage regulator can be reduced and a power loss can be reduced. A value of current flowing in the power supply circuit can also be decreased. Accordingly, an LNB with a reduced power consumption can be realized.

Abstract: A wireless communications device includes an antenna that receives a first signal at a first frequency and a second signal at a second frequency and converts the first and second signals into a composite signal. A first oscillator outputs a first oscillator signal at a first frequency and a second oscillator outputs a second oscillator signal at a second frequency. A demodulator receives the composite signal and the first and second oscillator signals. The oscillator signals are selected so that the demodulator generates a low frequency signal with components of the first and second signals occupying a common frequency band. The wireless communications device allows executing a “Soft Handoff” even when the first and second frequencies are different.

Abstract: The present invention relates to a phase lock oscillator which has a phase-locked loop including a reactive element and varies a reactance of the reactive element at an instant prior to an instant at which the phase-locked loop reaches a limit of maintaining its lock state, and relates to a communication equipment with the lock phase oscillator mounted therein. The phase lock oscillator and the communication equipment can flexibly adapt to variances in environment conditions and maintain stable and high service quality.

Abstract: DC offset is estimated in a wireless receiver during a period when receive energy is blocked from reaching a mixer within the receiver. The estimated DC offset value may then be used to reduce DC offset within the wireless receiver when a receive signal is subsequently being processed.

Abstract: A terminal includes at least one wireless communication application module (1) and a plurality of further application modules (4, 5, 6, 8). Multiple radio frequency clock signals are generated for the different modules having respective clock frequency characteristics and including at least first and second clock frequencies that are not integral multiples nor sub-multiples of each other nor of a third frequency. The clock generation comprises reference frequency means (14), fractional-N phase-locked loop frequency synthesizer means (15) responsive to the reference frequency means, and different automatic frequency control means for adjusting clock frequencies relative to received signals. The reference frequency means (14) is arranged to supply a common reference frequency signal to a plurality of the fractional-N phase-locked loop frequency synthesizer means (17, 18, 19, 25, 26, 41,42) that supply the first and second clock frequencies respectively for the application modules.

Abstract: A receiver has an adder for output intermediate-frequency signals of a plurality of receiving blocks, a demodulator for an added intermediate-frequency signal, adjustable reference-signal generator for supplying phase-shifted reference signals to the PLL circuits of the plurality of receiving blocks, and a plurality of switches. The switches are controlled when power is first supplied to the receiver such that the frequency-divided reference signals to the PLL circuits are in phase with one another. The adjustable reference-signal generator, upon tuning on power, is set in the phase-shift adjusted state stored immediately before previously turning off the power.

Abstract: A receiver for a wireless communication device is disclosed. The receiver comprises a plurality of frequency tines coupled to receive an intermediate frequency signal, each frequency tine of the plurality of frequency tines having a pair of NCOs; a comb filter coupled to the center frequency tine of the plurality of frequency tines; and a comparator circuit coupled to said plurality of frequency tines, the comparator circuit comparing two outputs of the plurality of frequency tines. A method of determining an intermediate frequency in a wireless communication device is also disclosed. The method comprises the steps of providing a plurality of frequency tines for receiving signals at a plurality of different intermediate frequencies; determining an approximate magnitude of a frequency offset from a center frequency; and determining the sign of the frequency offset.

Abstract: A local oscillator for use in an optoelectronic distance measurement system for generating a narrow-band HF signal for direct signal mixing with a reception signal generated by an avalanche photodiode (2) from a light signal impinging on the latter, with the depletion layer capacitance (CAPD) of the avalanche photodiode (2), which varies due to different influences and specimen scatter, is incorporated, as an element which (co-)determines the oscillator frequency, in a controllable HF resonant circuit whose HF resonant frequency is determined, for example, by the adjustable divider ratio of a PLL-circuit (1) which is acted upon by a phase-locked reference oscillator (6) and which controls the capacitance (C) of a capacitance diode (3) connected in parallel with the depletion layer capacitance.

Abstract: A method of intermediate frequency (i.f.) planning for radio transmitters and receivers involves predicting which i.f. or i.f. range will result in spurious emissions to or response from one or more “avoidance bands” being sources of unwanted signals or frequency bands closed to transmission, whereby to choose an i.f. or i.f. band which minimises such i.f. bands. The method may be carried out by computer software which may be embedded in a transmitter/receiver having means for varying its i.f.

Abstract: A transceiver suitable for larger scale of integration employs direct conversion reception for reducing the number of filters. Also, the number of VCOs is reduced by utilizing dividers to supply a receiver and a transmitter with locally oscillated signals at an RF band. Dividers each having a fixed division ratio are used for generating locally oscillated signals for the receiver, while a divider having a switchable division ratio are used for generating the locally oscillated signal for the transmitter. In addition, a variable gain amplifier for baseband signal is provided with a DC offset voltage detector and a DC offset canceling circuit for supporting high speed data communications to accomplish fast cancellation of a DC offset by eliminating intervention of a filter within a feedback loop for offset cancellation.

Abstract: A multiple channel receiver (200) includes a communications receiver synthesizer (204) and at least one numerically controlled oscillator (NCO) (406) that produce local oscillator signals that are derived from a common reference oscillator (202). A DSP (212) and CPU (214) perform automatic frequency control (AFC) by adjustment of the reference oscillator (202) based upon a signal received by a receive channel using the local oscillator signal produced by the communications receiver synthesizer (204). The CPU (214) also provides a synchronous indication of adjustments to the reference oscillator (202) to control circuitry for the at least one NCO (406) so that the configuration of the NCO (406) can be altered so as to maintain a substantially constant frequency output during the adjustment of the reference oscillator (202).

Abstract: A system and method for providing location based notifications, comprising a remote communications device, a communications network and a base station having a notification system. A personalization engine receives user preferences and transfers user information to a user preference repository; a preference profiler retrieves predefined user information from a registry for comparison with the user preferences; the preference profiler notifies a notification monitor and a location monitor of the comparative results; the location monitor retrieves location information from a user location repository and notifies the notification monitor of the location information, the user information, the user preferences and the user location being compared; and a notification gateway notifies the location based notification to the remote communications device.

Abstract: A phase locked loop that includes such a loop filter, the phase locked loop includes a difference detector, programmable charge pump, fixed loop filter, voltage controlled oscillator and adjustable divider module. The difference detector is operably coupled to determine a different signal based on differences in phase and/or frequency between a reference oscillation and a feedback oscillation. The programmable charge pump is operably coupled to generate a charge current based on the difference signal and a scaling signal. The fixed loop filter is operably coupled to convert the charge current into a control voltage. The voltage controlled oscillator generates an output oscillation based on the control voltage and the adjustable divider module generates the feedback oscillation based on the output oscillation and a divider value. The scaling module is operably coupled to produce the scaling signal based on the selected divider.

Abstract: A wireless communications device includes an antenna that receives a first signal at a first frequency and a second signal at a second frequency and converts the first and second signals into a composite signal. A first oscillator outputs a first oscillator signal at a first frequency and a second oscillator outputs a second oscillator signal at a second frequency. A demodulator receives the composite signal and the first and second oscillator signals. The oscillator signals are selected so that the demodulator generates a low frequency signal with components of the first and second signals occupying a common frequency band. The wireless communications device allows executing a “Soft Handoff” even when the first and second frequencies are different.

Abstract: A tuner architecture is disclosed that mixes an analog RF input signal and a digital local oscillator signal to generate a output signal at a desired IF frequency, including low-IF and zero-IF solutions. The tuner provides a number of advantages over previous implementations, such as improved performance for low-IF and zero-IF architectures and a significant reduction in interference between adjacent paths in a multiple tuner solution. Other features and variations can be implemented, if desired, and related methods can be utilized, as well.

Abstract: The invention relates to a kit of a local oscillator of an airborne VHF multimode communication transceiver. The local oscillator of the airborne VHF multimode communication transceiver comprises a temperature compensated crystal local oscillator, a direct digital synthesizer (DDS) and an input/output interface.

Abstract: A direct downconversion receiver combines a received RF signal and a local oscillator (LO) signal to form a combined signal. The local oscillator signal is also phase-shifted by approximately 90 degrees to form a quadrature signal. A mixer forms the product of the combined signal and the quadrature signal to produce a baseband output signal.

Abstract: In a mobile communication device, a method for compensating for a frequency adjustment in an oscillator shared between a communication circuit and a positioning signal receiver is provided. In one embodiment, the method begins to receive and store a positioning signal at a first time point. When, at a second time point, the operating frequency of the shared oscillator is adjusted, the frequency adjustment is recorded. After the positioning signal is completely received and stored, the processing of the positioning signal takes into consideration the frequency adjustment. In that embodiment, the processing hypothesizes a frequency shift in the received positioning signal. According to another aspect of the present invention, a method for determining the operating frequency of an oscillator detects a beginning time point of a reference signal received by the mobile communication device and enables a counter to count in step with a clock signal derived from the oscillator.

Abstract: A programmable IF bandwidth is achieved in either a transmitter or receiver using fixed bandwidth filters. A minimum of two IF frequencies are used. A fixed bandwidth filter that is equal to or greater than the desired IF bandwidth is used at each IF. The Local Oscillators (LO's) are tuned to frequency convert the desired signal to a frequency that is offset towards one bandedge of the fixed IF filters. A first mixer and LO relocates the desired signal to one end of a first fixed IF filter. A second mixer and LO relocates the filtered signal to the opposite end of a second IF filter. The desired bandwidth is obtained as the sum of the frequency offset of the desired signal from the nearest bandedge of the first IF filter and the frequency offset of the desired signal from the opposite bandedge of the second IF filter.

Abstract: A wireless communication apparatus prevents desensitization in a line signal frequency caused by clock signal harmonic. The wireless communication apparatus is provided with a receiver/demodulator for receiving a line signal of a predetermined frequency and for demodulating the line signal, a control section decoding the demodulated line signal using an operation clock signal, and a clock signal generating circuit supplying a clock signal. The control section controls the clock signal generating circuit to change a frequency of the clock signal in response to the line signal frequency, therefore, harmonic of the clock signal do not enter into a desensitization range corresponding to the line signal frequency.

Abstract: An architecture for a multiple-band wireless transceiver with quadrature conversion receiver and transmitter circuits. A common, or shared, local oscillator is used to provide the necessary frequency up and down conversion signals for the transmitter and receiver circuitry, respectively. Each of the transmitter and receiver circuits include multiple, e.g., three, signal paths for providing multiple-band operation. In the transmitter, the outgoing baseband data is quadrature modulated. The modulated data signals are then frequency up converted using another quadrature signal mixing process which avoids any need for image signal rejection filters within the signal transmission path. Similarly, in the receiver, quadrature signal mixing is used for the frequency down conversion process, thereby avoiding any need for image signal rejection filters within the signal reception path. The down-converted data signals are then quadrature demodulated to produce the incoming baseband data.

Abstract: A semiconductor device capable of reducing power consumption. In the semiconductor device having a plurality of data transmitter-receiver circuits using clock signals on frequencies prescribed in the unified standard as transmit/receive clock signals, an oscillator circuit and a clock generator circuit are provided for each data transmitter-receiver circuit and a supply of clock signals to the data transmitter-receiver circuits can be stopped by shutting off the power supply to the oscillator circuits and the clock generator circuits inside the plurality of data transmitter-receiver circuits individually with respect to each data transmitter-receiver circuit.

Abstract: A double-conversion tuner receives an RF signal having a number of channels and down-converts a selected channel from the plurality of channels. The double-conversion tuner includes a first mixer configured to up-convert the RF signal to a first IF signal using a first local oscillator signal. A first local oscillator includes a delta-sigma fractional-N phase lock loop to produce the first local oscillator signal. The delta-sigma fractional-N phase lock loop is configured to perform fine-tuning of the first local oscillator signal and to have a wide tuning range sufficient to cover the number of channels. A bandpass filter is configured to select a subset of channels from said first IF signal. A second mixer is configured to down-convert the subset of channels to a second IF signal using a second local oscillator signal. A second local oscillator generates the second local oscillator signal.

Abstract: Tunable upconversion mixers that have a controllable passband response and provide substantial image rejection, making costly post-mixing filtering at least optional, if not unnecessary for many applications. A single mixer is able to support several frequency bands (and/or be accurately tuned within one frequency band) by means of varying the capacitance in a tunable load circuit for the mixer circuit. The tunable mixer comprises a mixer circuit having inputs for receiving a signal to be upconverted and an oscillator signal to be mixed with the signal to be upconverted. The mixer generates a mixer output signal at a desired sideband frequency and an image signal at an image frequency.

Abstract: A radio receiver having a selectable first downconverter stage for each mode to convert radio frequencies to intermediate frequencies, a second downconverter stage to convert the intermediate frequencies to baseband frequencies, said second downconverter stage being common to both modes, and channel selection at baseband frequencies by means of re-configurable filtering. A radio receiver having a selectable first downconverter stage for each mode to convert radio frequencies to intermediate frequencies, a second downconverter stage to convert the intermediate to baseband frequencies, said second downconverter stage being common to all modes, and channel selection at baseband frequencies by means of re-configurable filtering.

Abstract: The present invention eliminates the need for an anti-aliasing filter in a receiver that employs an analog-to-digital converter. By maintaining a predetermined relationship between a local oscillator frequency and the sampling frequency of the analog-to-digital converter, aliasing that would normally occur in the desired pass band is avoided. More specifically, the frequency of the periodic signal provided to the mixer is an integer multiple of half the sampling rate of the analog-to-digital converter. In a preferred, non-limiting example embodiment, the sampling rate of the analog-to-digital converter FADC and the frequency of the local oscillator FLO are related by the following: FLO=n * FADC/2, where n is any positive integer.

Abstract: The invention relates to a tuner for converting a radio frequency signal into an intermediate frequency signal, said tuner comprising a voltage converter supplying a control signal, a mixer associated with an oscillator which is voltage-controlled by said control signal.

Abstract: A method of intermediate frequency (i.f.) planning for radio transmitters and receivers involves predicting which i.f. or i.f. range will result in spurious emissions to or response from one or more “avoidance bands” being sources of unwanted signals or frequency bands closed to transmission, whereby to choose an i.f. or i.f. band which minimises such i.f. bands. The method may be carried out by computer software which may be embedded in a transmitter/receiver having means for varying its i.f.

Abstract: A radio-frequency (RF) receiver includes a receiver analog circuitry and a receiver digital circuitry coupled together. The receiver analog circuitry receives an RF signal. The receiver analog circuitry processes the received RF signal and generates a digital signal that it provides to the receiver digital circuitry. The receiver digital circuitry includes a digital down-converter circuitry that mixes the digital signal provided by a receiver analog circuitry with a digital intermediate frequency (IF) local oscillator signal to generate a digital down-converted signal. The receiver digital circuitry also includes a digital filter circuitry that filters the digital down-converted signal to generate a filtered digital signal. The digital filter circuitry provides a notch at a frequency that corresponds to a residual DC offset of the receiver analog circuitry.

Abstract: A local oscillator for use in an optoelectronic distance measurement system for generating a narrow-band HF signal for direct signal mixing with a reception signal generated by an avalanche photodiode (2) from a light signal impinging on the latter, with the depletion layer capacitance (CAPD) of the avalanche photodiode (2), which varies due to different influences and specimen scatter, is incorporated, as an element which (co-)determines the oscillator frequency, in a controllable HF resonant circuit whose HF resonant frequency is determined, for example, by the adjustable divider ratio of a PLL-circuit (1) which is acted upon by a phase-locked reference oscillator (6) and which controls the capacitance (C) of a capacitance diode (3) connected in parallel with the depletion layer capacitance.

Abstract: A method for generating a local oscillation signal comprising two separate frequency converters, of which one frequency converter includes an output unit for generating an internal output signal to be used for its frequency conversion, and the other frequency converter employs the same internal output signal from the output unit as the local oscillation signal.

Abstract: A mobile radio telephone having a simplified architecture including a reduced number of integrated circuits and a reduced number of RF connections. A dual band, dual mode mobile phone can be constructed using either a single crystal reference oscillator or two crystals such that alternative symbol rates, channel spacings, or transmit/receive duplex spacings can be achieved.

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: A transceiver board for use in a cellular radiotelephone base station comprises a first cellular radio transceiver including a first controller that controls the operation of the first transceiver, a second cellular radio transceiver including a second controller that controls the operation of the second transceiver, common local oscillator that generates a tuning signal used by the first and second transceivers for tuning a radio signal, and an arbitrator that is connected to the first and second controllers and that determines which of the first and second controllers communicates with the common local oscillator. Preferably, the arbitrator is implemented by a programmable device such as a programmable logic device (PLD) that monitors the first and second controllers to determine which controller attempts to communicate with the common local oscillator first so that that controller is allowed to communicate with a common local oscillator to the exclusion of the other controller.

Abstract: A balanced differential radio receiver (100) has an antenna (64) operative for receiving a modulated signal. A first pair of mixers (110, 112) each having an input that receives an output (106, 108) of the antenna (64) and each of the first pair of mixers (110, 112) having an output (118, 120). A second pair of mixers (114, 116) each having an input that receives an inverse output (108, 106) of the antenna (64). A resistive adding circuit (122, 124) having a pair of inputs (118, 120). The inputs (118, 120) coupled to the output of the first pair of mixers (110, 112).

Abstract: A tuner is used in common for both terrestrial and satellite television reception. A second mixing stage is switched as a mixer for signal conversion into a second intermediate frequency during terrestrial television reception and is switched as a component of a FM-PLL demodulator during satellite television reception. The tuner is particularly suitable for television receivers and video recorders which receive signals from both a terrestrial antenna/signal source and from a satellite antenna/signal source.

Abstract: Diversity reception apparatus includes a number of receivers each having a distortion detector. There is a common output channel. A comparator compares the signals detected by detectors and provides a control signal to a selector or switching circuit that couples that receiver having the preferred received signal to the common output channel.

Abstract: In an earth-based receiving station for receiving radio signals transmitted from a satellite relay station, a common first frequency converter and at least two receivers are provided. One of the receivers is used as a control receiver to receive a CSC carrier frequency transmitted from the satellite, to generate a first local oscillator frequency phase-locked to the CSC carrier frequency, and to supply the first local oscillator frequency to the common first frequency converter. Other receivers are used as channel receivers for receiving channel frequencies. In case when the control receiver is in trouble, any other receiver can be used as a control receiver.