Abstract: The present invention provides a method for controlling a charging voltage of a 12V auxiliary battery for a hybrid vehicle, which can (1) improve charging efficiency of an auxiliary battery by increasing the output voltage of a DC-DC converter during cold start when the outside air temperature is low, (2) improve the charging efficiency of the auxiliary battery by increasing or decreasing the output power of the DC-DC converter according to the state of charge of the auxiliary battery and by increasing the output voltage of the DC-DC converter when many electrical loads are turned on, and (3) allow the DC-DC converter to provide continuous power supply for charging the auxiliary battery by turning on a main switch disposed between a high voltage battery and the DC-DC converter based on a reverse power conversion operation of the DC-DC converter even in the case where the voltage of the auxiliary battery falls below 9V.

Abstract: A capacitive parametric zero crossing detection circuit has a nonlinear voltage controlled capacitive device coupled to an input voltage to convert a zero crossing current pulse into zero crossing voltage signal.

Abstract: Provided is a receiver apparatus, including: a first receiver configured to receive a first signal having a first frequency band; and a second receiver configured to receive a second signal having a second frequency band, the second frequency band being different from the first frequency band, in which a signal path for the first signal and a signal path for the second signal share at least one component in a signal path for extracting an intermediate-frequency signal from a received signal, the component being configured to extract a signal of a particular channel from the received signal as the intermediate-frequency signal.

Abstract: Methods and apparatus for providing access to program channels, e.g., high definition programs and program channels which corresponding to a standard definition program and/or program channels are described. In accordance with the invention, a high definition auto tune function is supported. When enabled, in one exemplary embodiment, if a user selects a standard program definition channel, a check is automatically made to determine if a corresponding high definition program channel is available. The corresponding high definition program channel is a channel which provides the same program as on the selected standard definition channel but in high definition. When the auto tune function is enabled and a corresponding high definition channel is available, the device, e.g., set to box or tuner implementing the auto tune feature of the present invention, automatically tunes to the high definition channel instead of the standard definition channel.

Abstract: HDMI is a digital audio and video communications protocol commonly used in consumer electronics. HDMI is particularly synonymous with high fidelity audio and video. Even though HDMI is a digital communications protocol, the audio quality can be impaired by analog signal impairments and distortions even if there are no digital decoding errors. In particular, the very process by which the audio is converted from Digital (HDMI) to human audible “Analog Audio” can be prone to errors. This occurs when the Digital to Analog Converter (DAC) clock, which is derived from the HDMI TMDS clock or HDMI source, is “distorted” due to its jitter, resulting in erroneous sampling or outputting of vital audio samples, thereby reducing the audio quality of the experience. The present invention reduces the jitter on the TMDS clock, and hence the audio DAC clock, resulting in lower audio distortion.

Abstract: There is provided a delta-sigma A/D converter including a first integrator, a second integrator located on an output side of the first integrator, a quantizer located on an output side of the second integrator, and a first current D/A converter receiving an output of the quantizer and providing a negative feedback signal to an input side of the quantizer.

Abstract: A DC/DC converter 10 has a high-side transistor QH as a switching element and a low-side transistor QL as a synchronous rectifier element. A first primary electrode D and secondary primary electrode S of the high-side transistor QH are connected to an input voltage VIN and an external terminal T1, respectively. A detection transistor QD is provided in a row with the high-side transistor QH, and the ON voltage of the high-side transistor QH when ON is output as detection voltage VQD from the detection transistor QD. The output detection voltage VQD is added to a feedback voltage VFB1 by an adder CB, and inputted to a comparator CMP1. The ON period of a one-shot pulse PS1 outputted from the comparator CMP1 is regulated so as to be in direct proportion to the sum of the detection voltage VQD and the feedback voltage VFB1.

Abstract: Video processing arrangement including a host computer, a video asset coupled to the computer for generating video signals, and an interface for connecting the video asset to the computer to enable the display of the video signals on a monitor. The video asset includes primary elements such as a primary composite video module that produces different types of a primary video signal and outputs the primary video signal, and a secondary video source module that produces a secondary composite video signal and outputs the secondary composite video signal. The primary composite video module includes a memory component including a user-programmable sequence of bits representative of a video signal and user-programmable signal generators synchronized to the primary video signal output of the primary composite video module. The memory component includes four user specified pulse memories which each hold a series of arbitrary bit line patterns.

Abstract: A digital broadcast receiver is provided, including a receiver which receives a plurality of broadcast signals, a channel scanner which scans the plurality of broadcast signals and acquires service information (SI) related to the plurality of broadcast signals, and a controller which selects a broadcast signal having a preset type of SI from among the acquired SI, and updates channel information.

Abstract: A control device signals user inputs to an audio-video display. The control device may be configured as a pillow speaker and include a speaker for reproducing audio from the audio-video display. The control device is coupled to the audio-video display by wiring. Shared signals in the wiring are used to provide power to operate the control device and are used to signal the user inputs to the audio-video display. A touch panel is used to sense user inputs. The touch panel may be transparent with an underlay containing indicia of user-selectable commands located below the touch panel. The arrangement and selection of commands available to the user may be modified by changing the underlay.

Abstract: Methods and apparatus for providing access to program channels, e.g., high definition programs and program channels which corresponding to a standard definition program and/or program channels are described. In accordance with the invention, a high definition auto tune function is supported. When enabled, in one exemplary embodiment, if a user selects a standard program definition channel, a check is automatically made to determine if a corresponding high definition program channel is available. The corresponding high definition program channel is a channel which provides the same program as on the selected standard definition channel but in high definition. When the auto tune function is enabled and a corresponding high definition channel is available, the device, e.g., set to box or tuner implementing the auto tune feature of the present invention, automatically tunes to the high definition channel instead of the standard definition channel.

Abstract: In an embodiment, the present invention includes a latch circuit having a first input to receive a data signal and a second input to receive a clock signal. This latch circuit may have a first pair of transistors including a first transistor gated by the data signal and a second transistor gated by an inverted data signal and a second pair of transistors including third and fourth transistors gated by the clock signal. The first transistor may be coupled to the third transistor at a first inter-latch node and the second transistor coupled to the fourth transistor at a second inter-latch node. A reset circuit may be coupled to the latch circuit to maintain the first and second inter-latch nodes at a predetermined voltage level when the clock signal is inactive.

Abstract: A test system (200) for testing for missing or shorted parts within a tuner circuit includes a signal generator (202) for applying a harmonic-containing baseband time varying RF test signal to the tuner circuit. The tuner circuit is tuned to a harmonic of test signal. A detector 208 coupled to the baseband IF output of the tuner circuit detects the voltage generated in response to the applied RF test signal. A voltage measurement device (210) measures voltage detected by detector to provide an indication of the gain. Significant changes in the gain indicate missing part(s) or short circuits.

Abstract: The present invention includes an apparatus for distributing a received modulated RF signal to a plurality of tuners including a diplexer device. The diplexer device includes a plurality of filter circuits adapted to direct respective portions of the received modulated RF the signal to respective tuner devices. In an illustrated embodiment, the tuner devices supply tuned signals to a picture in picture display device. Also disclosed is a method of receiving a modulated ready of frequency signal and routing portions of the received signal to respective tuner devices using filter devices in a diplexer or multiplexer configuration.

Abstract: A monitoring apparatus includes a detection circuit, a filter circuit, an amplifying circuit, a regulation circuit, a delay and charging circuit, and a driving circuit. The detection circuit receives a video signal, and performs an operation to obtain an image signal from the video signal. The filter circuit obtains an average intensity of a luminance signal corresponding to the image signal. The delay and charging circuit charges an input capacitor when receiving a low level regulated signal from the amplifying circuit. The driving circuit activates an alarm when a charging voltage of the chargeable capacitor exceeds a predetermined value.

Abstract: An RF transceiver integrated circuit has a novel segmented, low parasitic capacitance, internal loopback conductor usable for conducting IP2 self testing and/or calibration. In a first novel aspect, the transmit mixer of the transceiver is a current mode output mixer. The receive mixer is a passive mixer that has a low input impedance. In the loopback mode, the transmit mixer drives a two tone current signal to the passive mixer via the loopback conductor. In a second novel aspect, only one quadrature branch of the transmit mixer is used to generate both tones required for carrying out an IP2 test. In a third novel aspect, a first calibration test is performed using one quadrature branch of the transmit mixer at the same time that a second calibration test is performed using the other quadrature branch, thereby reducing loopback test time and power consumption.

Abstract: A tracking filter includes a first buffer, an impedance transformer, an inductor, a first capacitive unit, a second capacitive unit and a second buffer. The first buffer has an input terminal for receiving an input signal. The impedance transformer is connected with an output terminal of the first buffer. The inductor is connected with a second terminal of the impedance transformer. The first capacitive unit is interconnected between the impedance transformer and a ground terminal. The second capacitive unit is interconnected between the inductor and the ground terminal. The second buffer is connected with the inductor for generating an output signal. When specified values of the impedance transformer, the first capacitive unit and the second capacitive unit are simultaneously increased, an operating frequency of the output signal is decreased, so that a gain value of the output signal to the input signal is maintained constant.

Abstract: The present invention discloses a broadcast reception device including a connection section for connecting to a smart antenna that switches directivity or a unidirectional antenna with fixed directivity connected; a first channel search section for executing channel search in the smart antenna; a second channel search section for executing channel search in the unidirectional antenna; a communication section for providing the connected smart antenna with power and a control signal; and a connection detection section for detecting a voltage of the communication section varied by voltage drop caused by the communication section connected to the smart antenna, and detect one of presence and absence of connection of the smart antenna based on a result of the detection, the first channel search section is selected to execute the channel search when the connection detection section detects the connection of the smart antenna, and the second channel search section is selected to execute the channel search when the c

Abstract: The present invention provides a television receiver capable of automatically identifying the kind of a tuner and controlling the tuner in accordance with the kind. In a television receiver having a tuner for receiving a television broadcast signal and a module for detecting an intermediate frequency signal output from the tuner while controlling the tuner and outputting a video signal and an audio signal, the tuner is provided with a circuit for changing predetermined output information which is output from the tuner in accordance with the kind of the tuner, and information indicative of correspondence relation between the predetermined output information and the kind of the tuner is stored in a memory. By collating the predetermined output information output from the tuner with the information stored in the memory at the power on, the kind of the tuner is identified and, according to the kind, the module is allowed to control the tuner.

Abstract: A display apparatus includes a display; a receiver which receives a broadcasting signal including a program with a data format; an image processing part which processes the received program according to an available data format; and a controller which controls the image processing part to display a message informing that both data formats are not matched on the display if the data format of the received program is not matched with the available data format to be processed by the image processing part.

Abstract: A radio wave receiving apparatus includes: an antenna to receive a radio wave; a tuning member to allow a reception frequency of the antenna to be tuned to an intended frequency, in which tuning member a frequency characteristic is variable; a receiving member to receive a reception signal from the antenna to demodulate a modulation wave; a positive feedback member to perform a positive feedback in a signal path including the tuning member; and a switching member to turn on/off a feedback operation of the positive feedback member.

Abstract: A multi-standard integrated television receiver is disclosed. According to the invention, a RF tracking filter is provided to receive a RF signal and then filter out a fifth order and above harmonics and a band-pass filter is provided to further eliminate harmonics. Moreover, a double quadrature mixer is provided to remove third order harmonics. Accordingly, the quality factor requirement of the RF tracking filter and the linearity requirement of the band-pass filter are relaxed. Thus, the RF tracking filter and the band-pass filter can be fully integrated without any external components.

Abstract: An image display device may have a display portion, a signal-processing portion, a power supply portion that supplies power to the display portion and the signal-processing portion, a user interface portion, and a control portion that controls the display portion, the signal-processing portion, and the power supply portion. An operation mode may include a waiting mode in which power supply to the display portion and the signal-processing portion stops, an image-display-waiting mode in which power is supplied to the signal-processing portion but power supply to the display portion stops, and an image display mode in which power is supplied to the display portion and the signal-processing portion. The control portion may switch the operation mode, based on the operation signal, from the waiting mode or the image-display-waiting mode to the image display mode or from the image display mode to the image-display-waiting mode.

Abstract: A system, apparatus and/or method provides frequency response adjustment of an RF input filter of an RF tuner based on impedance of an antenna system that is providing reception of RF signals to the RF tuner. The frequency response adjustment is preferably accomplished dynamically and/or with respect to each frequency tuned. Particularly, the system, method and/or apparatus provides compensation at the RF tuner level for mistuning effects produced on the RF tuner by antenna system impedance presented at the antenna input that is other than a designed for impedance. Frequency response of an RF input filter for the RF tuner is electronically adjustable with an independent or semi-independent control voltage signal based on one or more measured parameters of a tuning frequency. Frequency response adjustment may include adjustment of a center frequency of the RF input filter bandpass frequency range and/or altering the bandpass frequency range of the RF input filter.

Abstract: A digital tuner unit receiving a digital signal in a reception channel having a predetermined bandwidth is connected at a subsequent stage of an antenna device containing radiation conductors and varactor diodes. A digital reception signal output from the digital tuner unit is input to a demodulation circuit and subjected to demodulation. An SP level detection unit of the demodulation circuit detects levels of a plurality of spread pilot signals in the bandwidth of the reception channel, and obtains a correction amount for a tuning voltage so that a level difference can be reduced to a predetermined value or less using the correction amount. The SP level detection unit reports the correction amount to an antenna tuning control unit so that the tuning voltage to be supplied to the antenna device can be corrected using the correction amount.

Abstract: Systems and methods are provided for calibrating the control mechanism in a communication circuit to allow the communication circuit to maintain a desired output power level. The communication circuit includes a variable gain adjustment circuit and a power amplifier, which operate together to provide an output power level. A control circuit controls the variable gain adjustment circuit based on a default gain parameter, a high power threshold, and a low power threshold. A calibration circuit in the control circuit calibrates a default gain parameter to provide a desired output power. A power detector can detect the desired output power level to provide an output power measurement. The calibration circuit calibrates upper and lower power thresholds to provide an acceptable range of power variation around the output power measurement.

Abstract: An apparatus is capable of distributing an input signal to multiple tuners within a dwelling unit using an architecture that is advantageous in terms of layout and expandability. According to an exemplary embodiment, the apparatus includes an amplifier operative to receive an input signal having a plurality of channels, and to amplify the input signal to generate an amplified signal. A plurality of serially connected couplers is operative to couple the amplified signal to a plurality of tuners.

Abstract: A digital television autoprogramming and tuning method and apparatus. In a digital television which can tune both MPEG 2 and PSIP format signals, a method of tuning uses one or more tables of information populated during an autoprogramming process. For MPEG 2 channels, the physical channel equals the major channel number and can be directly tuned. For PSIP channels, the major channel indexes a TSID which is used to determine a physical channel. If the TSID does not correspond to the correct program, the correct TSID is determined from the Program Specific Information in the data transport stream 134 and the system re-tunes to the correct physical channel. The autoprogramming process sequentially steps through each physical channel and populates the autoprogramming tables with information about each channel it finds, saving only a single TSID for a given major PSIP channel.

Abstract: A TV tuner consisting of a least one low-noise amplifier, one mixer and one variable-gain amplifier plus two band-pass filters, the first of which is placed after low-noise amplifier and before the mixer, and the second of which is placed after mixer and before variable-gain amplifier. The filters are on-chip active devices equipped with on-chip frequency- and Q-tuning systems. The first band-pass filter is a real filter, such that its frequency response is symmetrical for positive and negative frequencies. The second band-pass filter is a complex filter, such that its frequency response has transmission for positive frequencies, but blocks negative frequencies. The low-noise amplifier includes gain control. The mixer is a complex-mixer consisting of two identical mixers driven by two local oscillator signals in quadrature.

Abstract: A serial data receiving apparatus includes a transistor, a resistor, and a diode, converts input data of an RS232 standard to data of a TTL/CMOS standard.

Abstract: A television tuner includes a first high-frequency circuit for receiving VHF-band television signals, a second high-frequency circuit for receiving UHF-band television signals, and an integrated circuit. The integrated circuit includes a first mixer, a second mixer, a first input terminal that is connected to an input terminal of the first mixer, and a second input terminal that is connected to an input terminal of the second mixer and that is adjacent to the first input terminal. The first high-frequency circuit is connected to the first input terminal, and the second high-frequency circuit is connected to the second input terminal through a switching diode. The switching diode is turned off when the VHF-band television signals are received and is turned on when the UHF-band television signals are received.

Abstract: The present invention provides a television receiver capable of automatically identifying the kind of a tuner and controlling the tuner in accordance with the kind. In a television receiver having a tuner for receiving a television broadcast signal and a module for detecting an intermediate frequency signal output from the tuner while controlling the tuner and outputting a video signal and an audio signal, the tuner is provided with a circuit for changing predetermined output information which is output from the tuner in accordance with the kind of the tuner, and information indicative of correspondence relation between the predetermined output information and the kind of the tuner is stored in a memory. By collating the predetermined output information output from the tuner with the information stored in the memory at the power on, the kind of the tuner is identified and, according to the kind, the module is allowed to control the tuner.

Abstract: A television tuner includes a tuning circuit having two first varactor diodes for changing a tuning frequency, a mixer for converting a television signal to an intermediate frequency signal, an oscillator having a second varactor diode, and a PLL circuit for outputting a tuning voltage for tuning the television signal. The tuning voltage is applied to cathodes of the first varactor diodes and the second varactor diode, and voltages of anodes of the first varactor diodes and the second varactor diode are higher at a time of receiving the television signal whose frequency is lower than or equal to a predetermined frequency than at a time of receiving a television signal whose frequency is higher than the predetermined frequency.

Abstract: A television tuner includes an IF output terminal for outputting an IF signal converted from a received television signal to an external source, and a channel-selection PLL circuit for converting a high voltage supplied from an external source to a tuning voltage and for supplying the tuning voltage to an internal tuned circuit. The IF output terminal and a high-voltage input terminal of the channel-selection PLL circuit are connected to each other via a first resistor.

Abstract: An integrated circuit is provided with a power supply terminal and an external circuit connecting terminal which is DC insulated from an internal high-frequency circuit and is connected to an external circuit. An interface is provided with an address identifying circuit having applied with an address identifying voltage corresponding to address data and for setting the interface to receive only channel selection data by the address identifying voltage. The address identifying circuit is connected to the external circuit connecting terminals, and a first resistor is connected between the power supply terminal and the external circuit connecting terminal. The external circuit connecting terminal is DC shorted to the ground, a second resistor is connected between the external circuit connecting terminal and the ground, or the external circuit connecting terminal is DC insulated from the ground.

Abstract: A TV tuner includes an Ultra High Frequency (UHF)/Very High Frequency (VHF) tracking filter, an UHF/VHF matching circuit and a single conversion Tuner IC. The UHF/VHF tracking filter includes a first Low-Temperature Co-fired Ceramics (LTCC) inductor, a first varactor diode and a fine-tune capacitor electrically connected to determine the maximum gain frequency of the UHF/VHF tracking filter. The UHF/VHF matching circuit includes a second LTCC inductance, a second varactor diodes and a fine-tune capacitor electrically connected to determine the maximum gain frequency of the UHF/VHF matching circuit.

Abstract: A band switchable type tuning circuit has first switch means interposed between a power supply Vcc and an anode of a switch diode, a first resistor whose one end is connected to a cathode of the switch diode, second switch means interposed between the other end of the first resistor and a ground, a second resistor connected between the power supply Vcc and a connection point of the first resistor and the second switch means, and the third resistor connected between the ground and a connection point of the first switch means and the anode of the switch diode. The first switch means and the second switch means are turned on or off together by means of a band switching voltage.

Abstract: A broadcasting receiver for receiving a digital broadcast of the invention has a sub-channel changing-dedicated operation key so that upon reception of an instruction sent from this operation key, such a sub-channel that is adjacent in a predetermined direction in the same main channel may be selected in switch-over. If the desired channel cannot be found in the predetermined direction when an upward channel-movement instruction is received, such a sub-channel is selected that has the largest or smallest channel number. Thus, it is possible to accommodate a digital broadcast that has a hierarchical construction consisting of the main channel and the sub-channels and also that has a frequently fluctuating channel configuration, thus avoiding a delay in time required for channel changing.

Abstract: The invention relates to a device and a method of installing digital or analogue broadcasting channels of a frequency band, each channel being centred on a nominal frequency subject to drift or an offset. In this method, each channel is successively installed by searching for it within a nominal capture span centred on the said nominal frequency, the channels are sought as a function of installing at least one previous channel. Application to a digital or analogue receiving device.

Abstract: A liquid crystal television receiver includes a DC power supply to generate and output tuning DC power, a receiving portion, a display portion, and a series regulator. Preferably, the receiving portion is fed the tuning DC power and receives a video signal, the display portion includes an active-matrix liquid crystal panel, a gate driver to generate a gate-on signal and drive a gate line and a data driver to drive a data line, allowable ranges of voltage of the tuning DC power and the gate-on DC power share a common range in which a voltage of the tuning DC power is set, the tuning DC power is fed to the gate driver, and the series regulator is provided on at least one of power supply paths to feed the tuning DC power from the DC power supply to the gate driver and to the receiving portion, and removes noise component.

Abstract: A television tuner contains a mixer 4 for converting a television signal into an intermediate frequency signal and outputting it, an intermediate frequency tuning circuit 5 for tuning the intermediate frequency signal, an intermediate frequency amplifier 7 provided in an integrated circuit 10 and connected to the intermediate frequency tuning circuit 5, and option circuits 2 and 3 provided at the side of the front stage of the mixer 4 for being switched into the operational state or non-operational state at a specific receiving band or channel. The integrated circuit 10 is provided with input terminals 10a and 10b for inputting the intermediate frequency signal output from the intermediate frequency tuning circuit 5 to the intermediate frequency amplifier 7 and a switch control circuit 9 for switching the operation of the option circuits 2 and 3, where the switch voltage output from the switch control circuit 9 is supplied to the option circuits 2 and 3 through the input terminals 10a and 10b.

Abstract: One embodiment of a tuner integrated circuit includes two mixer circuits, an IF amplifier circuit, three oscillation circuits, a PLL circuit, and a reference oscillation circuit. A plurality of terminals are provided at two sides of the tuner integrated circuit and are connected to these elements. Among the terminals, at least an oscillator-connecting terminal for connecting an externally provided oscillator to the reference oscillation circuit, a power supply terminal through which a power supply voltage is supplied, and a ground terminal connected to a ground are provided at one side of the tuner integrated circuit. The power supply terminal and the ground terminal are disposed adjacent to the oscillator-connecting terminal such that they sandwich the oscillator-connecting terminal therebetween.

Abstract: An oscillation frequency changing means is inserted between a tuner and an oscillator of local oscillator (56) of a high frequency receiving device, and the oscillation frequency changing means, in each frequency band received, changes the oscillation frequency characteristic of local oscillator (56) in relation to the tuning voltage supplied from PLL circuit (78), and operates in accordance with the frequency characteristic of tuning filter (52, 54, 62, 64) to obtain an oscillation signal varied just by a predetermined frequency, thereby making it possible to receive broadband channels of continuous VHF broadcast band and UHF broadcast band.

Abstract: Example burst signal sampling circuitry including synchronous separator circuit(s), waveshaping circuit(s), bandpass amplifier circuit(s), and burst separator circuit(s) is provided in order to extract burst signal(s) from video signal(s) output from video amplifier circuit(s). Level converting circuitry ACC detector/amplifier circuit(s) is provided in order to convert fluctuation in the burst signal(s) to DC voltage(s). This DC voltage(s) is fed back by way of intervening control circuit(s) to the cathode side(s) of input tuning variable capacitance diode(s) constituting frequency characteristics correction circuit(s) of input tuning circuit(s).

Abstract: For receiving a voice FM broadcast it has so far been necessary to separately provide an SAW filter and a voice intermediate frequency amplifier circuit and the freedom of circuit design has been limited. In the present invention there is used a variable filter circuit 15 (a variable filter means). The variable filter circuit 15 allows an intermediate frequency signal (IF) to pass therethrough, the intermediate frequency signal being outputted from a mixing circuit 14 as a constituent of a tuner means. The variable filter circuit 15 can change a limitation on the frequency band of the intermediate frequency signal passing therethrough. The frequency band of the intermediate frequency signal passing through the variable filter circuit 15 is thereby limited according to the type of a received broadcasting radio wave, and a VCO circuit 32 (a variable oscillator means) is controlled so as to change the oscillation frequency of an oscillation signal.

Abstract: A VHF tuning circuit includes two tuning inductance devices connected in series with each other and having a junction thereof connected to an input terminal, and a first switch diode connected in parallel with the two in series inductance devices, and turned OFF at least when tuning is performed with a low range of a VHF band. A UHF tuning circuit is connected to the input terminal through a second switch diode that is turned ON at least when tuning is performed with a UHF band. The second switch diode is turned OFF when tuning is performed with a low range of the VHF band.

Abstract: The level of the harmonics of oscillation signals for synchronous detection to be inputted to a mixer circuit for converting frequencies is suppressed low.

Abstract: A tunable receiver is disclosed including a plurality of select filters to perform an initial band selection, a variable-gain low noise amplifier (LNA) whose gain is controlled to prevent its output power level to exceed a pre-determined power threshold, a plurality of digitally-tunable tracking filters to pass signals within a selected channel and to reject signals in a corresponding image band, a second LNA to further amplify the received RF signal and to generate differential signal outputs, a down converting stage which converts the received RF signal to an IF signal while rejecting signals in the image band, an IF trap to further reject undesired signals present at the output of the down converting stage, an IF amplifier to amplify the IF signal to compensate for losses, an IF filter to provide channel select and reject undesirable signals, and a variable-gain IF amplifier to amplify the IF signal and maintain its power level within specification.

Abstract: A television tuner has a high frequency tuning circuit, a high frequency amplifier, a mixer, and an oscillating section. The tuning circuit is made up of an inductor and plural capacitors and at least one of the capacitors is selected and connected in parallel with the inductor; and the oscillating section has at least plural oscillators which are included in an integrated circuit. In the integrated circuit, the oscillators respectively have variable capacitors to vary a frequency of a local oscillation signal. Groups into which a receiving frequency band is divided correspond to the oscillators on the basis of one oscillator per group; and each of the oscillators generates local oscillation frequencies depending on television signals in the corresponding group.

Abstract: A worldwide television tuning system is configurable to the television standards and channel frequencies of multiple different countries based on a country's ITU long-distance country code. The tuning system maintains a country code table listing a plurality of countries according to their ITU codes. The tuning system also maintains multiple channel-to-frequency mapping tables that correlate channel numbers to corresponding frequencies for associated countries in the country table. The country table indexes the channel-to-frequency mapping tables. During configuration, a user or application selects a particular country by passing in the ITU code. The tuning system uses the ITU code to locate an entry for that country in the country code table. The table entry contains an index to an associated channel-to-frequency mapping table for the selected country. The tuning system loads and saves the channel-to-frequency mapping table for subsequent use.