Abstract: The present invention includes phase shifters, interrogators, methods of shifting a phase angle of a signal, and methods of operating an interrogator. One aspect of the present invention provides a phase shifter including a first power divider configured to receive a signal and provide plural quadrature components of the signal; plural mixers coupled with the first power divider and configured to scale the quadrature components using a phase shift angle; and a second power divider coupled with the mixers and configured to combine the scaled quadrature components to shift the phase angle of the input signal by the phase shift angle.

Abstract: An apparatus comprising a first circuit, a second circuit and a third circuit. The first circuit may be configured to generate an upconverted signal in response to an input signal and a first oscillation signal. The second circuit may be configured to generate a downconverted signal in response to the upconverted signal and as second oscillation signal. The third circuit may be configured to generate an output signal in response to the downconverted signal and a third oscillation signal derived from the second oscillation signal. The upconverting and downconverting may filter undesired channels from the output signal.

Abstract: A television (TV) receiver includes a multi-standard channel filter with a programmable intermediate frequency adapted to receive television signals in a variety of television standards and formats. In one embodiment, a receiver includes a tuner and a channel filter. The tuner receives input RF signals encoding information in one of a number of formats and converts the input RF signals to intermediate signals having an intermediate frequency (IF). The intermediate signals are coupled to the channel filter. The channel filter includes an anti-aliasing filter for filtering the intermediate signals, an analog-to-digital converter for sampling the filtered intermediate signals and generating a digital representation thereof, and a signal processor for processing the digital representation of the intermediate signals in accordance with the format of the input RF signal. The signal processor generates digital output signals indicative of information encoded in the input RF signal.

Abstract: A multiple purpose antenna system for installation on a highway truck to receive and transmit signals. The system includes an antenna for communication of electromagnetic frequency signals having multiple band widths, a multiplex unit coupled to the antenna having circuitry for simultaneously passing multiple signals of band widths, and a filter unit. The filter is coupled to the multiplex unit for filtering signals received from the multiplex unit into multiple sets of band width ranges. The sets include a first frequency range for use by a first receiver apparatus, a second frequency range for use by a second receiver apparatus, and a third frequency range for use by a third receiver apparatus. The filter unit may be included within a satellite electronic communications unit. The first receiver apparatus may be a weather band radio apparatus. The third receiver apparatus may be an AM/FM commercial radio.

Abstract: While a spectrum waveform of an output signal from a subtracter (207) is visibly monitored, an operator controls a variable phases shifter (208) based upon a second control signal (CL2) so that a shape of a spectrum waveform of an output signal from a subtracter (207) is approximated to a spectrum waveform of a desirable wave to change a phase of a local oscillation frequency signal from a local oscillator (206). As a result, a phase of a duplicated loop signal is changed. Also, the operator controls a variable attenuator (209) based upon a first control signal (CL1) so that a shape of this spectrum waveform is approximated to a spectrum waveform of a desirable wave (20) to change a signal level of the duplicated loop signal.

Abstract: A frequency arrangement with at least two successive heterodyne stages, one of which converts an input signal with an adjustable first frequency of a superposition oscillator that can be set in fine frequency increments into a first intermediate frequency, a second heterodyne stage that converts an input signal with a fixed second heterodyne frequency of a second superposition oscillator into a second intermediate frequency, the difference frequency between the first and second heterodyne frequencies is converted with an adjustable frequency divider into a lower frequency, which is then compared in a phase detector to the output frequency of a reference oscillator which is implemented as a synthesizer that can be set in fine frequency increments, the first superposition oscillator being synchronized with the output frequency of the reference oscillator via a phase control loop with the output signal of this phase detector, and the adjustable frequency divider preferably being a fractional N-divider with singl

Abstract: This patent describes a method and system which overcomes the LO-leakage problem of direct conversion and similar RF transmitters. To solve this problem a virtual LO™ signal is generated within the baseband which is tuned to the incoming RF signal. The virtual local oscillator (VLO) signal is constructed using signals that do not contain a significant amount of power (or no power at all) at the wanted output RF frequency. Any errors is generating the virtual LO signal are minimized using a closed loop correction scheme.

Abstract: A digital broadcast recorder capable of recording digital television (TV) signals includes a first frequency converter which converts a received digitally modulated TV signal into a first intermediate frequency signal having a frequency lower than that of the digitally modulated TV signal, the first intermediate frequency signal having a frequency in a standard TV band and useable in demodulating standard TV signals, a band-pass filter coupled to the first frequency converter, which selectively passes-through the first intermediate frequency signal, a phase-lock loop (PLL) circuit coupled to the first frequency converter, which controls an oscillation frequency of a local oscillator in the first frequency converter, a second frequency converter coupled to the band-pass filter, which converts the first intermediate frequency signal passed through the band-pass filter into a second intermediate frequency signal lower in frequency than said first intermediate frequency signal a digital demodulator coupled to the

Abstract: A CMOS implemented passive mixer circuit for improving linearity performance in wireless communication systems is described, including dual pairs of NMOS FETs and dual pairs of PMOS FETs. Each NMOS FET is connected in parallel with a corresponding PMOS FET. A local oscillator signal is provided to the gate of one FET while a 180-degree phase shifted local oscillator signal is provided to the gate of its complementary FET. Because the complementary FETs are driven by local oscillator signals that are 180 degrees out of phase, the NMOS FET is turned on for at least a portion of the positive cycle of the local oscillator signal and the PMOS FET is turned on for at least a portion of the negative cycle of the 180-degree phase shifted local oscillator signal. Distortion in the mixed output signal is thereby reduced.

Abstract: A tuner includes an input terminal, first to fourth band-pass filters, an automatic gain controller, first to third amplifiers, first and second mixers, first and second voltage controlled oscillators, first and second PLL ICs, a reference oscillator circuit, and an output terminal. The second PLL IC and the reference oscillator circuit are connected through a capacitor and an amplifier. An amplifier for reference oscillation, included in the first PLL IC is connected to the reference oscillator circuit through an inductor that defines an inductance device.

Abstract: A dual-band receiver for a wireless communication device having multi-slot capability. A first oscillator generates a relatively high frequency traffic LO signal. A second oscillator generates a first relatively low frequency signal, and a third oscillator generates a fixed low frequency signal. A first mixer mixes the first and fixed low frequency signals to produce a relatively high frequency monitor LO signal. A switch selects the traffic LO signal when the receiver is in a traffic slot and the monitor LO signal when the receiver is in a monitor slot. The selected LO signal is provided to a second mixer along with the received signal to produce a first IF signal. A third mixer mixes the first IF signal and the fixed frequency signal to produce an output signal.

Abstract: Precision in adjustment of filtering characteristics of a high frequency device is improved by providing a high frequency device comprising a first filter, a frequency converter, and a second filter. The high frequency device comprises a high frequency filter for extracting signal components in a predetermined frequency band from an input signal; a frequency converter for converting frequency of the signal components extracted by the high frequency filter; and an intermediate frequency filter for extracting signal components in a predetermined frequency band from the signal components, the frequency of which is converted by the frequency converter. The high frequency device further comprises a bypass circuit provided in parallel to the intermediate frequency filter downstream of the high frequency filter; and a switching mechanism including a switching circuit for switching connection of a signal path downstream of the high frequency filter to either the intermediate frequency filter or the bypass circuit.

Abstract: A low-priced digital broadcast receiving tuner suitable for miniaturization will be provided. According to the present invention, it is possible to provide a low-priced digital broadcast receiving tuner having higher productivity as well as a less number of components than a conventional tuner because, on one surface of an insulating board, there is formed a first tuner while, on the other surface thereof, there is formed a second tuner, and therefore a single insulating board can be shared.

Abstract: The present system for determining the phase and amplitude of a radio occultation signal modifies the traditional Open Loop tracking process to maximize the signal-to-noise ratio, minimize the sampling rate, and also preserve the structure of the radio occultation signals. A radio occultation system includes a transmitter system, a receiver system, and a post-processing system. The receiver system receives the radio signal that is transmitted by the transmitter system through the earth's atmosphere, where it is occulted, and down converts the received radio occultation signal to generate a down converted signal based on a phase model that uses a refractivity climatology. The receiver system then low pass filters the down converted signal and samples the in-phase and quadrature components of the down converted and low pass filtered signal.

Abstract: A transceiver is disclosed having a zero intermediate frequency to low intermediate frequency receiver and a direct upconversion transmitter. Calibrations may be performed to minimize direct current voltage offset and in-phase and quadrature-phase path mismatch after downconversion. Automatic gain control is performed prior to downconversion and after upconversion to minimize the introduction of mismatch.

Abstract: A digital broadcast recorder capable of recording a digital television (TV) signals, includes a first frequency converter which converts a received digitally modulated TV signal into a first intermediate frequency signal having a frequency lower than that of the digitally modulated TV signal, the first intermediate frequency signal having a frequency in a standard TV band and useable in demodulating standard TV signals, a band-pass filter coupled to the first frequency converter, which selectively passes-through the first intermediate frequency signal, a phase-lock loop (PLL) circuit coupled to the first frequency converter, which controls an oscillation frequency of a local oscillator in the first frequency converter, a second frequency converter coupled to the band-pass filter, which converts the first intermediate frequency signal passed through the band-pass filter into a second intermediate frequency signal lower in frequency than said first intermediate frequency signal a digital demodulator coupled to

Abstract: A broadband television receiver front end for receiving a broadband RF input signal and outputting an IF output signal is disclosed. A high pass input filter on the front end attenuates carrier signal frequencies that lie below a cut off frequency of said high pass filter. Thereby advantageously allowing for a number of carrier signals to propagate below the cutoff frequency in such a manner that these signals have a decreased effect on television signals propagating within a television signal band. By high pass filtering on the input a low noise amplifier disposed for receiving a filtered signal from the high pass filter does not amplify noise caused by lower frequency carriers. As a result an amplified signal provided to up-conversion and a down-conversion mixers results in an increased immunity to noise in the output IF signal from the front end.

Abstract: A switch circuit is provided for at least one of a previous stage of a VHF-band frequency converter and a previous stage of a UHF-band frequency converter. Each switch circuit passes a signal when a frequency converter at a subsequent stage of the switch circuit is operating, and does not pass a signal when the frequency converter at the subsequent stage of the switch circuit is not operating.

Abstract: A CMOS implemented passive mixer circuit for improving linearity performance in wireless communication systems is described, including dual pairs of NMOS FETs and dual pairs of PMOS FETs. Each NMOS FET is connected in parallel with a corresponding PMOS FET. A local oscillator signal is provided to the gate of one FET while a 180-degree phase shifted local oscillator signal is provided to the gate of its complementary FET. Because the complementary FETs are driven by local oscillator signals that are 180 degrees out of phase, the NMOS FET is turned on for at least a portion of the positive cycle of the local oscillator signal and the PMOS FET is turned on for at least a portion of the negative cycle of the 180-degree phase shifted local oscillator signal. Distortion in the mixed output signal is thereby reduced.

Abstract: The present invention includes phase shifters, interrogators, methods of shifting a phase angle of a signal, and methods of operating an interrogator. One aspect of the present invention provides a phase shifter including a first power divider configured to receive a signal and provide plural quadrature components of the signal; plural mixers coupled with the first power divider and configured to scale the quadrature components using a phase shift angle; and a second power divider coupled with the mixers and configured to combine the scaled quadrature components to shift the phase angle of the input signal by the phase shift angle.

Abstract: Methods and apparatus, in accordance with the present invention, use at least two phase-locked loop based frequency synthesizers to provide a synthesized frequency output having a step size of X, where X is less than the step size of any of the at least two phase-locked loop based oscillators. By combining a first signal having a first frequency, with the output of a first frequency synthesizer having a first frequency step size, NX, to produce an intermediate signal which is in turn combined with the output a second frequency synthesizer having a second frequency step size, MX, an output signal is produced. M and N are related such that i times M=N±1, and i, M and N are integers. By varying the output frequency of the first and second frequency synthesizers, the frequency of the output signal is changed by steps of X, where X is less than the step size of either the first or second frequency synthesizers.

Abstract: An LO generation circuit generates an LO signal by doubling and quadrupling the frequency of a VCO signal. The frequency doubling and quadrupling provides high VCO-RF isolation as well as suppression of spurious noise signals in the LO output. The frequency doubler takes a quadrature signal input and utilizes mixer cores having double balanced transistor pairs to provide an output signal having doubled frequency but maintaining the phase balance of the input signal.

Abstract: Receiving apparatus for digital television signals digitizes a final intermediate frequency signal supplied from a triple-conversion radio receiver and synchrodynes the digitized final intermediate frequency signal to baseband. The triple-conversion radio receiver selects one of a plurality of digital television signals for upconversion to that portion of the electromagnetic frequency spectrum above the channels that are used for television broadcasting, amplifies a first intermediate-frequency signal in a first intermediate frequency band generated by that upconversion, amplifies a second intermediate-frequency signal in a second intermediate frequency band generated by downconverting the amplified first intermediate-frequency signal, and supplies a third intermediate-frequency signal in a third intermediate frequency band generated by downconverting the amplified second intermediate-frequency signal.

Abstract: A tuning circuit, as for a television receiver or video recorder, employs switchable tuning circuits including micro-electronic electro-mechanical switches for selecting the ones of an array of capacitors and/or inductors as is useful in tunable circuits. The array of capacitors and/or inductors and micro-electro-mechanical switches of the switched tuning matrix is formed on an integrated circuit or an electronic circuit substrate along with amplifiers and other electronic elements of the tuning circuit for which the switched tuning matrix is employed. The switchable capacitance and inductance matrices are well suited for use in the resonators employed in the pre-selector filters, post-selector filters and oscillators of electronic tuners, such as those employed in television receivers and video recorders.

Abstract: A frequency arrangement with at least two successive heterodyne stages, one of which converts an input signal with an adjustable first frequency of a superposition oscillator that can be set in fine frequency increments into a first intermediate frequency, a second heterodyne stage that converts an input signal with a fixed second heterodyne frequency of a second superposition oscillator into a second intermediate frequency, the difference frequency between the first and second heterodyne frequencies is converted with an adjustable frequency divider into a lower frequency, which is then compared in a phase detector to the output frequency of a reference oscillator which is implemented as a synthesizer that can be set in fine frequency increments, the first superposition oscillator being synchronized with the output frequency of the reference oscillator via a phase control loop with the output signal of this phase detector, and the adjustable frequency divider preferably being a fractional N-divider with singl

Abstract: A dual-band receiver for a wireless communication device having multi-slot capability. A first oscillator generates a relatively high frequency traffic LO signal. A second oscillator generates a first relatively low frequency signal, and a third oscillator generates a fixed low frequency signal. A first mixer mixes the first and fixed low frequency signals to produce a relatively high frequency monitor LO signal. A switch selects the traffic LO signal when the receiver is in a traffic slot and the monitor LO signal when the receiver is in a monitor slot. The selected LO signal is provided to a second mixer along with the received signal to produce a first IF signal. A third mixer mixes the first IF signal and the fixed frequency signal to produce an output signal.

Abstract: A first analog differential signal V1p and a first analog differential signal V1n are applied to the respectively commonly-connected bases of two sets of differential pairs which are constructed of transistors Q1 to Q4. A commonly-connected collector of Q1 and Q4 is used as an output terminal Vop, whereas a commonly-connected collector of Q2 and Q3 is used as another output terminal Von. Collectors of Q11 and Q12 are connected to the respective commonly-connected emitters of these differential pairs. Parallel resonant circuits are connected to the respective emitters of Q11 and Q12, and the emitter-to-emitter path is connected by R15. Input circuits 101 and 102 are connected to the respective bases of Q11 and Q12. A second analog differential signal V2p and a second analog differential signal V2n are inputted to these input circuits 101 and 102. The transistors Q12 and Q14 of the input circuits 101 and 102 constitute current mirror circuits in connection with Q11 and Q13.

Abstract: A signal convertor for modulating or demodulating an input signal x(t), comprising: a synthesizer for generating wideband mixing signals &phgr;1 and &phgr;2, which vary irregularly over time, where &phgr;1*&phgr;2 has significant power at the frequency of a local oscillator signal being emulated; a first mixer coupled to said synthesizer for mixing said input signal x(t) with said mixing signal &phgr;1 to generate an output signal x(t) &phgr;1; and a second mixer coupled to said synthesizer and to the output of said first mixer for mixing said signal x(t) &phgr;1 with said mixing signal &phgr;2 to generate an output signal x(t) &phgr;1 &phgr;2.

Abstract: A method for converting the frequency of an electrical signal, where an input signal is received, a first local signal and a second local signal of a different phase than the first local signal, are generated. A first product signal is obtained by mixing said input signal with the first local signal and a second product signal is obtained by mixing said input signal with the second local signal. The first and second product signals are combined together. The mixing of the input signal with the first local signal and the mixing of the input signal with the second local signal occurs in alternating time periods. The same mixing element is used for processing two or more branches in order to avoid imbalance in the mixed signals due to usage of separate, mismatching, mixing elements. The invention also relates to radio devices implementing the method described above.

Abstract: A receiver that downconverts input signals modulated using first, second, third and fourth modulation formats to a common intermediate frequency range. The first and second modulation formats are transmitted to the receiver in a first frequency range, the third modulation format is transmitted to the receiver in a second frequency range, and the fourth modulation format is transmitted to the receiver in a third frequency range. The input signals are provided to first, second and third band selection filters that respectively select first, second and third frequency ranges. A first downconverter is coupled to an output of the first band selection filter, and downconverts signals from the first frequency range to the common intermediate frequency range.

Abstract: The invention provides a simple solution for a broadband transmitter/receiver for which the working bandwidth is split into at least two non-contiguous sub-bands. The invention uses a filtering means 50 which comprises at least two band-pass filters 51 and 52 provided with switching means 53 and 54. The use of two switched filters 51 and 52 makes it possible to use a single synthesizer 6 to scan two sub-bands of the working bandwidth. The frequency synthesizer 6 operates for one sub-band in supradyne mode and for the other sub-band in infradyne mode. In a variant, the invention uses a third filter and divides the bandwidth into three sub-bands.

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 tuner, for example, for a television receiver, includes a UHF and a VHF section and a mixer oscillator stage. It is known that the VHF frequency band has to be split in at least two parts to handle the VHF signals. To that end, the mixer oscillator stage uses two separate VHF oscillators and a detector to switch tuned parts of the VHF section. In this way, the performance of the tuner is improved.

Abstract: A dual channel receiver (100) includes a front end bandpass filter (120) that has a front end bandwidth, a first mixer (130), a second mixer (135), and two essentially identical receiver back ends (190, 195). The front end bandpass filter splits a received signal into a first signal (121) and a second signal (122) of essentially equal signal strengths and provides out of band isolation between first and second signal outputs (123, 124). The first mixer is coupled to the first signal and to a high side injection signal (131), and generates a first mixer output signal (132). The second mixer is coupled to the second signal and to a low side injection signal (136), and generates a second mixer output signal (137). Each of the two essentially identical receiver back ends is coupled to one of the first and second mixer output signals.