US20100149431A1 - Active Inductor Circuits for Filtering in a Cable Tuner Circuit - Google Patents
Active Inductor Circuits for Filtering in a Cable Tuner Circuit Download PDFInfo
- Publication number
- US20100149431A1 US20100149431A1 US12/711,815 US71181510A US2010149431A1 US 20100149431 A1 US20100149431 A1 US 20100149431A1 US 71181510 A US71181510 A US 71181510A US 2010149431 A1 US2010149431 A1 US 2010149431A1
- Authority
- US
- United States
- Prior art keywords
- filter
- tuner
- signals
- signal
- active
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Images
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03J—TUNING RESONANT CIRCUITS; SELECTING RESONANT CIRCUITS
- H03J1/00—Details of adjusting, driving, indicating, or mechanical control arrangements for resonant circuits in general
- H03J1/0008—Details of adjusting, driving, indicating, or mechanical control arrangements for resonant circuits in general using a central processing unit, e.g. a microprocessor
- H03J1/0041—Details of adjusting, driving, indicating, or mechanical control arrangements for resonant circuits in general using a central processing unit, e.g. a microprocessor for frequency synthesis with counters or frequency dividers
- H03J1/005—Details of adjusting, driving, indicating, or mechanical control arrangements for resonant circuits in general using a central processing unit, e.g. a microprocessor for frequency synthesis with counters or frequency dividers in a loop
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03J—TUNING RESONANT CIRCUITS; SELECTING RESONANT CIRCUITS
- H03J3/00—Continuous tuning
- H03J3/02—Details
- H03J3/06—Arrangements for obtaining constant bandwidth or gain throughout tuning range or ranges
- H03J3/08—Arrangements for obtaining constant bandwidth or gain throughout tuning range or ranges by varying a second parameter simultaneously with the tuning, e.g. coupling bandpass filter
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/06—Receivers
- H04B1/16—Circuits
- H04B1/26—Circuits for superheterodyne receivers
- H04B1/28—Circuits for superheterodyne receivers the receiver comprising at least one semiconductor device having three or more electrodes
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
- H04N21/40—Client devices specifically adapted for the reception of or interaction with content, e.g. set-top-box [STB]; Operations thereof
- H04N21/41—Structure of client; Structure of client peripherals
- H04N21/426—Internal components of the client ; Characteristics thereof
- H04N21/42607—Internal components of the client ; Characteristics thereof for processing the incoming bitstream
- H04N21/4263—Internal components of the client ; Characteristics thereof for processing the incoming bitstream involving specific tuning arrangements, e.g. two tuners
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N5/00—Details of television systems
- H04N5/44—Receiver circuitry for the reception of television signals according to analogue transmission standards
- H04N5/50—Tuning indicators; Automatic tuning control
Definitions
- FIGS. 5 c and 5 d illustrates block schematic diagrams of selectively activatable lowpass and highpass filter circuits, respectively, incorporating the filter units illustrated in FIGS. 5 a and 5 b respectively;
- FIG. 7 b illustrates a block schematic diagram of a filter similar to the filter shown FIG. 7 a and including a switchable and variable gain feature;
- Radio frequency RF signals passing through the input filter 101 are amplified by an amplifier 102 .
- the amplifier 102 operates with a gain as determined by a delayed AGC signal.
- the amplifier 102 may be provided by either a variable gain amplifier or a variable attenuator coupled in series with a fixed gain amplifier. In any event, this requires that the amplifier 102 be a low noise amplifier (LNA) having a high linearity with respect to the entire television band of frequencies and one that offers a wide dynamic range with respect to received RF signal amplitudes.
- LNA low noise amplifier
- the amplifier 102 has a transmission band that is sufficient to pass the entire television band.
- the second IF filter 113 may be constructed on the same integrated circuit substrate as the other elements of tuner, or it may be a discrete off-chip device.
- the amplifiers 112 and 114 are used to provide proper impedances for the SAW filter 113 as well as to provide gain to maintain system noise performance.
- the amplifier 112 must provide a powerful signal at the relatively low impedance preferred for operation of the SAW filter. Heat generated by the power amplification and the SAW filter attenuation is significantly large as compared with other functions in the prior art TV tuner.
- a broadband television tuner according to embodiment of the invention is shown in block diagram form.
- RF signals are received in the tuner 800 through input filters 301 a through 301 n .
- Each input filter 301 in the form of for example those filters illustrated in FIGS. 4 , 6 , 7 a and 7 b , is a switchably selectable filter for passing a selected range of frequencies within the frequency range across the television frequency band.
- the switchably selectable filter 301 passes any one selected channel through careful switching.
- the selected passband range for each filter is typically a range about a selected channel and is of sufficient size to provide good linearity across the channel passband.
Abstract
An integrated front-end filter for a tuner provides an array of from several to a multitude of passbands, each for passing at least one but less than all channels designated in a band of frequencies. Each passband is exclusively selectable. The integrated front end filter includes at least one active filter unit with an active reactance element in either of fixed and variable filter configurations and a decoder coupled to said at least one active filter unit and being responsive to a control signal for selecting a one of the passbands. In one example a multitude of active filter units of fixed filter configuration provide the multitude of passbands. Each data is stored at a predetermined location and reproduced in response to a corresponding control data signal from a tuner controller. Each data characterizes one of the plurality of passbands. The filter element is switchable from one passband to another in response to the control data signal. Lower power dissipation and lesser requirements of an on-following integrated circuitry tuner permit a reduction of “off chip” connections and cost.
Description
- The invention relates to the area of cable tuner circuits and more specifically to the area of active inductor and capacitor circuits for use in filtering within cable tuner integrated circuits.
- Cable tuner circuits are used to receive a television signal from a television signal provider and to tune into a single channel within the television signal in order to present audio and video information from that channel to an end user. Cable tuners that operate using a superheterodyne circuit for use in a superheterodyne method of processing television signal information are commonplace. A superheterodyne receiver converts a desired signal to an intermediate frequency (IF) for filtering using a fixed bandpass filter. Signals having been passed through the fixed bandpass filter are processed by a second primary component of the receiver. A fixed bandpass filter is preferred because the filter characteristics are more readily and precisely determinable and hence the desired signal is more readily distinguishable from noise and other unwanted signals. Surface acoustic wave (SAW) filters are exemplary of the state of the art fixed bandpass filters used in television tuners.
- SAW filter, brought upon a significant change in tuner design. With the use of SAW filters, some discrete filter components such as capacitors and manually tuned inductors used within the tuner circuit were reduced in number. With the use of SAW filters, filtering performance is improved within tuners as compared to prior techniques. Additionally, through the use of SAW filters, tuners were manufactured that required less space and were somewhat less costly than their counterparts. However, the SAW filter, which is fabricated on a ceramic substrate, is an off-chip device. It is also a rather low impedance device, and thus, requires low impedance matching to its input port. Additionally with the use of SAW filters, prior signal amplification requirements result in complications such as significant amplifier power consumption. Furthermore, broadband circuits, especially amplifier circuits, tend to consume more power as compared to narrower band circuits. Consequently, as the upper frequency for receivable TV signals increases, the power consumption of broadband amplifiers increases, particularly when used in combination with SAW filters. Heat dissipation and heat concentration in the already reduced surface area of a small TV tuner adds heat stress to the circuit components therein as well as to nearby elements of the electronic apparatus. The consequent heat stress thus unfavorably affects the functional reliability of both the tuner and any nearby elements. Furthermore, when more electrical components that are used within tuner circuits, more signal delays are observed as well as signal artifacts.
- A need therefore exists to provide an improved filter in cable tuner circuits that consumes less electrical power than conventional designs. It is therefore an object of the invention to provide a television tuner having filters that are integrable within a semiconductor substrate and one that lends itself to miniaturization.
- In accordance with the invention there is provided a tuner for receiving information signals within a channel selected from within a plurality of channels within a predetermined frequency band, the tuner comprising: a first filter for providing a passband, the passband being characterized by a bandwidth sufficiently broad to admit signals in at least one of the plurality of channels with lesser attenuation than other signals; an input port for receiving information signals and conducting the received information signals to the first filter; an output port for conducting any signals having been admitted by the first filter; and, superheterodyne circuitry including a mixer and a second filter for processing any signals coupled thereto and to provide them via a second output port and discriminating the received information signals within the selected channel, wherein at least one of the first filter and the second filter comprises active and passive elements including an artificial inductance.
- In accordance with the invention there is provided an integrated front end filter in a tuner for providing an array of passbands, each for passing at least one but less than all channels designated in a band of frequencies, each passband of said array of passbands being exclusively selectable, the integrated front end filter comprising: a control signal input port for receiving a control signal; at least one active filter unit including an active reactance element in either of fixed and variable filter configurations; and, a decoder coupled to said at least one active filter unit and being responsive to the control signal for selecting a one of the passbands.
- In accordance with the invention there is provided a method of tuning to a predetermined signal having a predetermined frequency band from within a plurality of channels comprising the steps of: receiving the plurality of channels; providing a filter having a bandwidth being sufficiently broad to admit the signal signals in at least one of the plurality of channels with lesser attenuation than other signals, the filter comprising active and passive elements including an artificial inductance; filtering and amplifying a channel from the plurality of channels using the filter.
- In accordance with the invention there is provided an integrated circuit tuner front end, responsive to a tuner controller signal, for tuning to a designated information modulated signal from a plurality of multiplexed information modulated signals each in a predetermined band of frequencies, comprising: an input port for receiving the multiplexed information modulated signals; a first filter for passing all the multiplexed information modulated signals and for attenuating signals that are other than the multiplexed information modulated signals; a first amplifier for amplifying all the passed multiplexed information modulated signals from the first filter; a first IF filter for receiving the amplified and passed multiplexed information modulated signals from the first amplifier, the first IF filter for selecting at least one of a designated information modulated signal; a frequency conversion circuit for receiving a selected at least one of a designated information modulated signal and for converting a baseband frequency thereof; and, a second IF filter for receiving the converted signal from the frequency conversion circuit and for passing a single designated information modulated signal to an output port thereof, the integrated tuner circuit absent an amplifier circuit electrically between the first IF filter and the second IF filter.
- In accordance with the invention there is provided an integrated front end filter in a tuner for providing an array of passbands, each for passing at least one but less than all channels designated in a band of frequencies, each passband of said array of passbands being exclusively selectable, the integrated front end filter comprising: at least one active filter unit including an active reactance element in either of fixed and variable filter configurations; and, a decoder coupled to said at least one active filter unit and being responsive to a control signal for selecting a one of the passbands.
- Exemplary embodiments of the present invention will be described in conjunction with the following drawings, in which:
-
FIG. 1 illustrates a block schematic diagram of a prior art television tuner with double conversion in accordance with that shown in referenced as prior art in the U.S. Pat. No. 6,177,964; -
FIG. 2 illustrates a block schematic diagram of a prior art television tuner intended for manufacture by integrated circuit manufacturing methods, substantially as disclosed in the U.S. Pat. No. 6,177,964; -
FIG. 3 illustrates a block schematic diagram of an example of an active parallel resonant circuit, useful for providing a filter and intended for integrated circuit manufacture; -
FIG. 4 illustrates a block schematic diagram of an example of a switchably selective filter including an active parallel resonant circuit as illustrated inFIG. 3 ; -
FIGS. 5 a and 5 b illustrates block schematic diagrams of lowpass and highpass filter circuit units, respectively, where any of which are variously useful for providing a filter in a tuner; -
FIGS. 5 c and 5 d illustrates block schematic diagrams of selectively activatable lowpass and highpass filter circuits, respectively, incorporating the filter units illustrated inFIGS. 5 a and 5 b respectively; -
FIG. 6 illustrates a block schematic diagram of another example of a switchably selective filter including active high pass and low pass circuits as illustrated inFIGS. 5 c and 5 d; -
FIG. 7 a illustrates a block schematic diagram of an example of a filter including an active switchably tunable parallel resonant circuit useful for providing a filter in a tuner; -
FIG. 7 b illustrates a block schematic diagram of a filter similar to the filter shownFIG. 7 a and including a switchable and variable gain feature; -
FIG. 8 illustrates a block schematic diagram of an example of a tuner which includes a filter at an input port thereof, in accordance with an embodiment of the present invention and intended for manufacture by integrated circuit manufacturing methods; and, -
FIG. 9 illustrates a variation of the prior art tuner shown inFIG. 2 , where filters are replaced with active filter and thus obviate the need for two amplifier circuits in accordance with another embodiment of the invention. - The prior art television (TV) tuner illustrated in
FIG. 1 is shown as being state-of-the-art in a discussion of prior art U.S. Pat. No. 6,177,964, entitled “Broadband Integrated Television Tuner”. - Referring to
FIG. 1 , the prior art TV tuner is described as being highly miniaturized, but not fully integrated. The prior art TV tuner is intended to reside within in a single metallic shielding structure, not shown. The shielding structure houses a printed circuit board, upon which, all of the tuner components are mounted and electrically connected. Hence the prior art TV tuner is designed as a module, which is intended for mounting on various printed circuit boards to allow for direct connection of the input and output signals to appropriate terminations within a television receiving system. The metallic shielding structure prevents undesired external signals from interfering with the operation of the prior art TV tuner and prevents the prior art TV tuner from radiating signals that might otherwise interfere with the operation of external devices. - The prior art TV tuner includes three integrated circuits: a
preamplifier mixer circuit 405, an intermediate frequency (IF) and baseband signal processor 410 and frequency synthesizer, and an Inter Integrated Circuit (IIC or I2C)bus interface 415. The prior art TV tuner also includes discrete components, including abandpass filter 404, a bandpass and imagereject notch filter 412, a surface acoustic wave (SAW)filter 416, avideo carrier filter 424, and an audiocarrier phase shifter 460. - The prior art TV tuner receives a standard television RF signal from either an
antenna 402 or a cable system connection (not shown) through thebandpass filter 404. Thefilter 404 is a narrow bandpass tracking filter which attenuates most of the television channels in distinction to the desired channel so that the potential of any interference from any undesired signals is reduced. Thebandpass filter 404 reduces the image response caused by afirst mixer 408 and also attenuates signals, which are not present in a fairly narrow (100 MHz) range about the desired signal. Finally, as the prior art TV tuner is specifically intended to operate with antenna supplied signals, known interference signals, such as FM broadcast, shortwave service signals, signals in the intermediate frequency band, and Citizen Band radio signals, are specifically rejected by thefilter 404. Thebandpass filter 404 is comprised of discrete elements, including capacitors, inductors and varactor diodes. - A
preamplifier 406, in the preamplifier andmixer circuit 405, receives signals from the output port of thebandpass filter 404 and raises the signal level as much as 10 dB with a minimum increase in noise level, typically 8-10 dB. The gain of thepreamplifier 406 is controlled by an automatic gain control (AGC)circuit 438, so that when a very strong signal enters the prior art TV tuner, overall gain is reduced, resulting in less distortion in thepreamplifier 406. - An output signal of the
preamplifier 406 is sent to a bandpass and imagereject notch filter 412, with the same basic requirement of minimizing the passage of potential interference signals.Filter 412 is external to the preamplifier andmixer circuit 405 and is comprised of discrete elements, including capacitors, inductors and varactor diodes. - An output signal from the bandpass and image reject
notch filter 412 then propagates to themixer 408, in the preamplifier andmixer circuit 405. Themixer 408 mixes the output signal from thefilter 412 with a local oscillator signal received from an output port of afrequency synthesizer 442 in the frequency synthesizer andI2C bus interface 415. Thefrequency synthesizer 442 is operated to provide the local oscillator signal having a frequency chosen to be higher than the desired receiver carrier by 43.75 MHz, and thus a difference signal is output from themixer 408 at 43.75 MHz. Due to the operation of themixer 408, there is an image signal created at 91.5 MHz above the frequency of the input signal, which is removed by thefilter 404 and thefilter 412 under control of theI2C 415. As the signal frequency of thefrequency synthesizer 442 is tuned to receive signals of different carrier frequencies, thebandpass filters - The
frequency synthesizer 442 receives an input frequency reference signal (usually 16 bits) and outputs status signals, AUTOMATIC FREQUENCY CONTROL (AFC) ERROR and FREQUENCY (FREQ) LOCK. Additionally, a tuning signal, which is used by a voltage controlled oscillator (VCO) (not shown) in thefrequency synthesizer 442, is output fromfrequency synthesizer 442 to thebandpass filters - The difference signal at 43.75 MHz output from the
mixer 408 passes through a surface acoustic wave (SAW)filter 416, which reduces the bandwidth of the signal to only one channel (6 MHz for the NTSC standard) and applies a linear attenuation in frequency known as the Nyquist slope around the visual carrier frequency. The linear attenuation by theSAW filter 416 converts this signal from a vestigial sideband signal to one that is equivalent to a single sideband with an added carrier signal. A significant disadvantage of theSAW filter 416 is that it is typically very lossy, having a loss of about 25 dB across its passband. Hence, a low output impedance preamplifier (not shown) amplifies the input signal provided to the off chip SAW filter by a corresponding amount to minimize noise effects. Unfortunately, heat is generated by the power amplification and the SAW filter attenuation. This heating is significantly large as compared with other functions in the prior art TV tuner. - The output signal from the
SAW filter 416 is brought on chip and is received by an IFamplifier 420 in the IF and baseband signal processor 410. TheIF amplifier 420 provides an output signal that is gain controlled by an automatic gain control (AGC)circuit 438, prior to further signal processing. - The output signal from the
IF amplifier 420 is received by avideo detector 422 and is also sent off-chip to the externalvideo carrier filter 424, where at this stage video demodulation is performed. Thevideo detector 422 is a mixer with its local oscillator input port connected to the output port of thevideo carrier filter 424 via acarrier amplitude limiter 426. The output signal from thecarrier limiter 426 is an in-phase representation of the video carrier signal limited to remove any amplitude modulation. The output signal from thecarrier limiter 426 is received by thevideo detector 422, which mixes the output signal of thecarrier limiter 426 with the output signal ofIF amplifier 420. AnAFC frequency discriminator 440 is used in the prior art TV tuner to detect any difference between the carrier frequencies in the video carrier signal from thecarrier limiter 426 and a known valid carrier frequency reference to produce an error signal. The error signal drives thefrequency synthesizer 442 in a direction for reducing the error between the output signal ofcarrier limiter 426 and the known valid carrier frequency reference signal. The output signal from thevideo detector 422 is a baseband video signal combined with several high frequency mixing artifacts, where avideo baseband filter 430 removes these artifacts. The output signal fromvideo baseband filter 430 is fed to a synchronization pulse clamp (sync clamp) 432, which sets the level of the sync pulses to a standard level. The output signal fromsync clamp 432 is sent to a noise inverter 434, which removes any large noise spikes from the signal. The output signal from the noise inverter 434 is sent to avideo buffer 436, which is usually configured to drive circuit board impedances of about 1000 to 2000 ohms via a video output port. - The output signal from the noise inverter 434 is also sent to the
AGC circuit 438, which compares the level of the synchronization pulses to a signal blanking level to measure the incoming signal strength, and generates a gain control signal. The gain control signal is used by theIF amplifier 420 andRF preamplifier 406 to dynamically adjust the gain of the prior art TV tuner for the desired signal level at the video output port. - The baseband video signal at the output port of the
video detector 422 also includes an audio signal in the form of a frequency modulated (FM) subcarrier signal at 4.5 MHz. The FM subcarrier is transmitted to a second audio detector, in this example an FM quadrature demodulator. The FM quadrature demodulator includes a mixer, 450 and an audiocarrier phase shifter 460. The audiocarrier phase shifter 460 shifts the audio subcarrier of 4.5 MHz by 90 degrees. Themixer 450 mixes the FM subcarrier signal with the 90 degree phase shifted signal to provide a baseband audio signal, which is filtered by a lowpass (30 kHz)filter 452 to remove any undesired high frequency components. The output signal from thelowpass filter 452 is passed to anaudio buffer 454 that provides an audio signal at an audio port. - A serial
digital interface 444 receives SERIAL DATA and SERIAL CLOCK input signals to provide control and update status for the television receiver. - The bandpass filters 404 and 412 are typically comprised of a plurality of capacitors, inductors and varactor diodes. The
video carrier filter 424 is usually comprised of three discrete elements: an inductor and two capacitors. Likewise, audiocarrier phase shifter 460 is also comprised of an inductor and two capacitors. In addition to the circuit elements shown as discrete components outside of thecircuit elements FIG. 1 , other discrete components (not shown) are connected to the IF and baseband signal processor 410 and to thefrequency synthesizer 442 for tuning purposes. Several external capacitors, inductors and/or varactor diodes typically tune thefrequency synthesizer 442. Thevideo buffer 436 and theaudio buffer 454, typically employ external discrete elements, such as resistors, capacitors and/or transistors. Thevideo baseband filter 430 andlowpass filter 452 may also employ external inductors and capacitors. All external components electrically connected to any of theintegrated circuits - Referring to U.S. Pat. No. 6,177,964, Birleson et al. teach a broadband television tuner, as is shown in the block diagram of
FIG. 2 . RF signals in a range of 55 Mhz to 806 Mhz are received in the tuner through aninput filter 101. Theinput filter 101 operates to attenuate signals above an input cut-off frequency corresponding to the highest frequency expected in the television band. As distinguished from the prior art TV tuner shown inFIG. 1 , theinput filter 101 is not tuned to select a few channels but instead passes all channels in the television band from approximately 50 MHz to 800 MHz. - Radio frequency RF signals passing through the
input filter 101, are amplified by anamplifier 102. Theamplifier 102 operates with a gain as determined by a delayed AGC signal. Theamplifier 102 may be provided by either a variable gain amplifier or a variable attenuator coupled in series with a fixed gain amplifier. In any event, this requires that theamplifier 102 be a low noise amplifier (LNA) having a high linearity with respect to the entire television band of frequencies and one that offers a wide dynamic range with respect to received RF signal amplitudes. Preferably theamplifier 102 has a transmission band that is sufficient to pass the entire television band. Theamplifier 102 functions to control high input signal levels in the received RF signal since the tuner is capable of receiving signals from a variety of sources, such as an antenna or a cable television line. Typically, one or several antenna channel signals are strong in power, while the remainders are much weaker. This requires that theamplifier 102 have a very broad dynamic range in order that both the weaker signals and the stronger signals are received satisfactorily. In contrast, cable television signals may have signal strengths of +15 dBmV and may comprise 100 cable channels. Theamplifier 102 must regulate in accordance with the varying signal levels in this broadband of received channels. - A
mixer 103 receives input signals from theAGC amplifier 102 and alocal oscillator 104. A first IF signal is generated in themixer 103 and is provided to a first IFfilter 109. The first IFfilter 109 is a bandpass filter that provides coarse channel selection. As a matter of design choice, the first IFfilter 109 may be constructed on the same integrated circuit substrate asmixers filter 109 may be a discrete off-chip device such as a radio frequency. SAW filter. The first IFfilter 109 is constructed to select a narrow band of channels, or perhaps only a single channel, from the television signals in the first IF signal. - A
mixer 110 mixes the first IF signal from the first IFfilter 109 with a second local oscillator signal from alocal oscillator 111 to generate a second IF signal. Themixer 110 may be an image rejection mixer, if necessary, to reject unwanted image signals. The characteristics of the first IFfilter 109, determines whether or not themixer 110 should function to provide image rejection. If image frequencies of any desired channel are adequately attenuated by the first IFfilter 109, then themixer 110 is typically a standard mixer. - Tuning phase locked loop (PLL)
circuits 105 controllocal oscillators bus interface 108 so that the picture carrier of a particular channel in the RF television signal spectrum appears at 43.75 MHz in the second IF signal. Of course, some signals at other frequencies may be provided depending on the standards in a particular region or country where the TV tuner is intended for use. The tuningPLL circuits 105 receive reference signals from areference oscillator 106, which is driven by a 5.25MHz crystal 107. TheI2C interface 108 provides control input signals to the tuner 10 and monitors the status of the tuner 10 and the tuningPLL circuits 105. - In operation, the front end of the TV tuner receives the entire television band through the
filter 101 and theamplifier 102. Themixer 103 up-converts the RF input signal so that a selected channel in the RF signal appears at a first IF frequency that is selected to pass through thefilter 109. The first IF frequency is then down-converted to a second IF frequency of 43.75 MHz by themixer 110. The frequency of the first local oscillator signal varies depending upon the specific channel desired in the RF signal. The second local oscillator is also optionally tunable when the second IF frequency is selected to be other than the typical 43.75 MHz. - Following the
mixer 110, anamplifier 116, under the control of the AGC, amplifies the second IF signal. Signals being passed by the second IFfilter 113 either remain on-chip for further processing or can be provided to an off-chip device, such as a decoder (not shown), through abuffer 115. Theamplifier 102 and theamplifier 116 operate in conjunction to control the overall signal level preparatory to further processing bycircuit elements 118, 120-133. These circuit elements are connected as shown to provide an IF andbaseband signal processor 135. - It is suggested that the second IF
filter 113 may be constructed on the same integrated circuit substrate as the other elements of tuner, or it may be a discrete off-chip device. Theamplifiers SAW filter 113 as well as to provide gain to maintain system noise performance. Theamplifier 112 must provide a powerful signal at the relatively low impedance preferred for operation of the SAW filter. Heat generated by the power amplification and the SAW filter attenuation is significantly large as compared with other functions in the prior art TV tuner. - It is an object of the present invention to replace the SAW filters used in prior art tuner circuits by other filter circuits. However, a significant restraint in RF and microwave IC design stems from the difficulty in realizing an integrated passive inductor with sufficiently high Q over a broad bandwidth. Large space requirements, low inductance values and low Q factors, make these inductors unsuitable for precision applications, such as for example use in television tuner circuits. It has now been found that, by replacing the SAW filters with active inductor circuits, the active inductor circuit allow for larger inductance values to be realized in a small device footprint as well as provide stability for precision application, such as for use in television tuner circuit. Active inductors are known in the art of circuit design and are described in detail in U.S. Pat. Nos. 5,726,613; 6,028,496; and, 6,130,832 as well as in the literature and are well known to those of skill in the art. A tunable active inductor is described in U.S. Pat. No. 6,211,753.
- Advantageously, active inductors are integratable within semiconductor substrates and as such a cost of tuner circuit manufacture using active inductors is reduced because off-chip pins previously used to couple SAW filters to the integrated portion of the tuner circuits are now eliminated. Furthermore, because of improved impedance matching characteristics of these active inductors, amplifiers used to amplify signals prior to filtering by the SAW filters are advantageously eliminated.
- Referring to
FIG. 3 , an active parallelresonant circuit unit 30, including anartificial inductance 31 with a pair ofterminals V. A capacitance 32, in the form of a pair of varactor diodes, is connected across the pair ofterminals 31 a to provide a functional LC (inductor capacitor) parallel resonant circuit, to form an active parallel resonant circuit unit (APR). The varactor diodes have predetermined dimensions and are operated at an appropriate bias, provided by a source not shown, to provide a required capacitance value for thecapacitance 32. In a somewhat similar configuration, a pair of varactor diodes (not shown) provides for a capacitive element in theartificial inductance 31 and determines its effective inductance value. TheAPR 30 is an example of a parallel resonant circuit which functions as an impedance to a signal applied across theterminals circuit unit 30 exhibits maximum impedance at a resonant frequency determined by the values of theartificial inductance 31 and thecapacitance 32, and lesser impedances for frequencies other than the resonant frequency. The qualities (Q) of theartificial inductance 31 and thecapacitance 32, determine the sharpness of the frequency of maximum resonance, as is well known to those of skill in the art. - Referring to
FIG. 4 , a switchably selectable bandpass filter is shown for use in an embodiment of the invention, having a narrow bandpass. Theresonant circuit unit 30 is identified as an active parallel resonance (APR) 30. TheAPR 30 is coupled in a feedback network between input and output ports of an inverting amplifier 51. A field effect transistor (FET) 48 is also connected in the feedback network between the input and output ports of the amplifier 51, via source and drain electrodes as shown. The input port of the amplifier 51 is switchably coupled to receive signals via aFET 46. The amplifier 51 is also switchably coupled to supply signals from its output port via aFET 47. Preferably the amplifier 51 is of a high a gain and of a low noise performance as is practically convenient in integrated circuit technology. A power supply lead V is coupled via aFET 45 with a voltage switched (VS) power feed lead. The VS power feed lead is connected to supply operating voltage to theAPR 30 and the amplifier 51, and to control the conductive states of the FETs 46-48. The narrow bandpass filter ofFIG. 4 is inactive and isolated unless adecoder 40 has received a predetermined code for selecting of the filter. When the filter is selected thedecoder 40 activates the filter into an ON state by switching voltage onto the VS power feed lead via theFET 45. Otherwise thedecoder 40 maintains the bandpass filter in an OFF state, with only the decoder being powered. Input signals are resistively coupled to the input port via theFET 46 operating with predetermined impedance. Amplified signals are coupled from the amplifier 51 via theFET 47. TheAPR 30 functions as a nearly all-pass filter providing almost total negative feedback, except for a narrow frequency band of 7 or 8 MHz where little signal energy is passed. TheFET 48 is either an enhancement mode, or a depletion mode device, configured to operate with predetermined impedance when voltage is supplied to its gate electrode from the VS lead. The impedance of theFET 48 determines a resistance in parallel with theAPR 30, and consequently the effective gain of the amplifier 51 in the narrow frequency band of 7 or 8 MHz. Because the filter shown inFIG. 4 utilizes active elements, in the form of varactors and APR, it is hereinbelow referred to as an active bandpass filter unit (ABP). - Referring to
FIG. 5 a, a low pass circuit unit (LP) is provided by theartificial inductance 31 and thecapacitance 32, where thecapacitance 32 is connected between signal ground and the terminal 31 b. In operation, a signal applied to theartificial inductance 31, from a signal source (not shown) at the terminal 31 a, is conducted to terminal 31 b via an impedance that is proportional in value to the value of theartificial inductance 31 at the signal frequency. A portion of the signal appearing atterminal 31 b is conducted with an impedance value that is in inverse proportion with respect to the value of thecapacitance 32 and with respect to its signal frequency. Thus, as is well known to those of skill in the art, signal energy available to a load (not shown), connected at the terminal 31 b, depends upon the source's impedance in series with the impedance of theartificial inductance 31 and the load's impedance in parallel with the impedance of thecapacitance 32. In another arrangement, not shown, thecapacitance 32 is connected between the terminal 31 a and ground. - Referring to
FIG. 5 b, a high pass circuit unit (HP) is provided by theartificial inductance 31 and thecapacitance 32, as shown. Thecapacitance 32 is connected between a signal source (not shown), having source impedance, and a load (not shown), having load impedance, while theartificial inductance 31 is connected between the signal source and signal ground. A signal applied to the high pass circuit unit is conducted via the impedances of theartificial inductance 31 and the sum of the impedances of thecapacitance 32 and the load. The effects of theartificial inductance 31 and thecapacitance 32, with respect to signal frequencies is well known as illustrated in the preceding paragraph. Thus, signal energy available to the load depends upon the source's impedance in series the impedances of thecapacitance 32 and is loaded by the impedance of theartificial inductance 31. In another arrangement, not shown, theartificial inductance 31 is connected between the terminal 31 a and the load. - Referring to
FIG. 5 c, an active low pass filter circuit unit (ALP) 36 is shown for use in an embodiment of the invention. TheALP 36 utilizes the low pass circuit unit, illustrated inFIG. 5 a, connected with input andoutput buffer amplifiers ALP 36 contains varactor diodes and other active components (not illustrated). - Referring to
FIG. 5 d, an active high pass filter circuit unit (AHP) 38 is shown for use in an embodiment of the invention. TheAHP 38 utilizes the high pass circuit unit illustrated inFIG. 5 d connected with input andoutput buffer amplifiers AHP 38 characteristics are substantially constant irrespective of source and load impedances, since theAHP 38 contains varactor diodes and other active components (not illustrated). - Furthermore, each of the input and
output buffer amplifiers artificial inductance 31, are connected with a voltage switched (VS) power feed lead, such that when the filter is not needed for the instant operation of a tuner, it is switched OFF and thus does not contribute to electrical power consumption of the tuner circuit. - In the ALP and AHP filter examples shown in
FIGS. 5 c and 5 d, when the power to any one filter is switched OFF, theinput buffer amplifier 33 is arranged to have an input impedance tending toward infinity, while theoutput buffer amplifier 34 is likewise arranged to have an output impedance tending toward infinity. In other words, each filter that is switched OFF, via the VS lead, is effectively isolated from the signal path of the tuner circuit. In an array of circuits based upon filter circuits generally similar to those ofFIG. 5 c andFIG. 5 d, parasitic loadings of a signal source and outputs of switched OFF filter circuits are advantageously avoided. - The filter illustrated in
FIG. 6 is similar to the filter illustrated inFIG. 4 , with the exception of theAPR 30 being replaced by theALP filter 36 and theAHP filter 38. The ALP and AHP filters 36 and 38, in this example, are arranged to have mutually exclusive passbands and roll-offs defining a mutual stopband with 6 db points at least a MHz outside of a channel width, in the negative feedback path of the filter. As in found in the filter depicted inFIG. 4 , the ON impedance of theFET 48 primarily determines the attenuation, or gain, of the filter at the center of the channel frequency. Although the filter shown inFIG. 6 requires more circuit elements, and hence consumes more integrated circuit substrate area for its implementation than does the filter ofFIG. 4 , the roll off characteristics are more flexible for design purposes. - The filter illustrated in
FIG. 7 a is similar to that illustrated inFIG. 4 , however in this example the APR is variable, in the form of a variable APR (VAPR) 39. Rather that being biased by fixed elements determined at the time of circuit fabrication, diode elements of thecapacitance 32 and theartificial inductance 31 are biased by voltages developed in digital to analog converters labeled D/A CAP 42 and D/A IND 43, respectively. The D/A converter 42 develops a bias voltage for varactor diodes in a capacitive portion of theVAPR 39 and the D/A converter 43 develops a bias voltage for varactor diodes in an artificial inductance portion of theVAPR 39. The bias voltages are developed in response to data provided by a frequency look up table 41. In operation, the decoder is responsive to the most significant few bits of filter selection data to activate the filter elements. The bits of lesser significance are translated in the frequency table 41 and supplied as data to the D/A converters channel 2 TV program signals, and a user desired to change to channel 4, the D/A converters switch the filter to operating with a passband for passing channel 4 TV program signals. - The switchably selective filter shown in
FIG. 7 b is similar to the filter shown inFIG. 7 a, but also includes a D/A converter 44, with an output port coupled to a gate electrode of a FET 49. In this example, the FET 49 is shown to be a dual gate FET. The other of the gate electrodes is coupled with an AGC signal from on-following tuner circuitry. In operation, the gain of the filter is specified in the data of the channel selection and is further adjusted in response to the AGC signal developed in the on-following tuner circuitry to regulate the overall gain in the signal path. The passband of the filter, as depicted in either ofFIGS. 7 a and 7 b, is controlled to switch from one channel to another channel in response to data supplied from any of the controller circuits used in the various tuners discussed hereinbelow. - Referring to
FIG. 8 , a broadband television tuner according to embodiment of the invention is shown in block diagram form. RF signals are received in thetuner 800 throughinput filters 301 a through 301 n. Each input filter 301, in the form of for example those filters illustrated inFIGS. 4 , 6, 7 a and 7 b, is a switchably selectable filter for passing a selected range of frequencies within the frequency range across the television frequency band. In this fashion, the switchably selectable filter 301 passes any one selected channel through careful switching. The selected passband range for each filter is typically a range about a selected channel and is of sufficient size to provide good linearity across the channel passband. For example, each range covers 70 MHz of bandwidth with 20 MHz of overlap to ensure that each channel is somewhat central within a range. In a preferred embodiment, a simple switching network directs the signals through one of a plurality of filters, each filter passing a predetermined range corresponding to a selected channel. Filter 301 operates to attenuate signals above an input cutoff frequency corresponding to a frequency in the television band above the selected channel frequency. - Following filter 301, the RF signal passes through delayed
AGC amplifier 302, which operates in conjunction withIF AGC amplifier 316 to control the overall signal level intuner 800.Amplifier 302 is a variable gain amplifier or a variable gain attenuator in series with a fixed gain amplifier. The preferred embodiment ofamplifier 302 comprises a low noise amplifier (LNA) with a high linearity that is sufficient to pass the entire television band. Alternatively, each of the plurality of filters comprises a LNA for amplifying the associated frequency band. - Though the remainder of the circuit functions similarly to prior art tuner circuits by reducing the noise in the overall tuner signal path it also allows for integration of filter components within either the filter 301 or
subsequent filters - When filter 301 is integrated,
LNA 302 is optionally designed integrally therewith to provide linearity across the selected range for each possible selected range. As such, design simplification of the overall LNA results. - Because of the need for low power tuner devices for use in various applications, it is highly advantageous to amplify less of the incoming signal—reduce bandwidth—and thereby to limit power consumption by not amplifying signals as much within the
tuner 800. Thus, by advantageously using active filters in the forms of those shown inFIGS. 4 , 6, 7 a and 7 b, significant power savings are realized in thetuner circuit 800. No longer are signals amplified within the tuner circuit in order to enable satisfactory operation of the SAW filters. - The
filter array 300 ofFIG. 4 is formed from a plurality ofintegrated filter circuits 301a through 301 n including active inductors therein. Because of the variety and nature of active inductors, their use in thetuner 30 is highly advantageous. Typically, a small amount of linearity is lost when straying from prior art discrete filter components. Here, that loss of linearity is insignificant because of the nature of the filtering process, which is used to reduce noise within the tuner circuit. Of course, the use of active inductors within the filters 301 allows for integration of the selectable filter component within the tuner, thereby reducing parts count, size, and significantly reducing power consumption of the tuner. Also, pins are not required for providing filtered signals to the tuner integrated circuit and thus the integrated circuit components used to support those input pins are advantageously obviated. - Furthermore, for reduced
tuner 800 power consumption, only a small portion of the front-end filters in thetuner 800 are active at any instant, thereby offering reduced power consumption, where the power consumption is less than that of the power consumption of the bulk of the integrated circuit. Furthermore, the reduced spectrum provided to the on following superheterodyne circuitry reduces filtering requirements in the on-following circuitry, making on-chip filters more practical. - When the
filter 301 a to 301 n is selected by data from thetuner controller 1108, the filter is switched to the appropriate channel in accordance with stored data at the storage location addressed by the selection data, and operates with the desired passband. Accordingly, thetuner 800 is tunable over a plurality of decades of the television frequency band. As it may be difficult to construct a variable filter, which is entirely integrated and variable from tens of megahertz up to almost a gigahertz, several filters of appropriately different geometries are each individually selectable for receiving a corresponding portion of the television signal band. - Optionally, when an active inductor forms part of the filter circuit, it is used to provide some signal amplification as well. Thus, an amplifier/filter component is designed for each selectable band, thereby reducing amplifier complexity since the amplifier is a narrow band device that operates within a known band. Small amounts of nose outside this known band are not of concern.
- The resulting
tuner 800, according to this embodiment of the invention, provides enhanced filtering over prior art tuner devices with integrated input filtering and thereby reduces overall cost and improves performance. Further, since the dynamic range of each of the active inductors is known within its filter, dynamic range concerns in inductor design are obviated. - Referring to
FIG. 9 , a tuner circuit 900 is shown in accordance with another embodiment of the invention, where each of the three filters, 101, 109 and 113 (prior artFIG. 2 ) are replaced withintegrated filters filters filter 613, amplification is integratable with the active filter, thereby obviating the need for twoamplifiers active filter 613 is one channel wide. - Of course, the replacement of a single filter within the tuner circuit with an integrated circuit, including an active inductor, is advantageous over the prior art. Besides reducing pin count, the active inductors are capable of facilitating tuner design by providing gain within the active filter functional block. This advantageously provides signal switching, improves reliability of the overall tuner and reduces the tuner's power consumption. Reducing tuner power consumption advantageously allows for its use in new low power applications. Furthermore, by providing active inductor filter circuits within the tuner, it allows the tuner to operate using significantly less power and thus potentially allows for designing a tuner that enables energizing power to be received from the coaxial cable service provider's cable feed. Heretofore this has been considered impractical because of the significant power consumption of a multitude of tuners, which are typically connected to any cable feed.
- Numerous other embodiments may be envisioned without departing from the spirit or scope of the invention.
Claims (15)
1. A tuner for receiving information signals within a channel selected from within a plurality of channels within a predetermined frequency band, the tuner comprising:
a first filter for providing a passband, the passband being characterized by a bandwidth sufficiently broad to admit signals in at least one of the plurality of channels with lesser attenuation than other signals;
an input port for receiving information signals and conducting the received information signals to the first filter;
an output port for conducting any signals having been admitted by the first filter; and,
superheterodyne circuitry including a mixer and a second filter for processing any signals coupled thereto and to provide them via a second output port and discriminating the received information signals within the selected channel,
wherein at least one of the first filter and the second filter comprises active and passive elements including an artificial inductance.
2. A tuner as defined in claim 1 wherein at least one of the first and second filters is integrated within a semiconductor substrate.
3. A tuner as defined in claim 1 wherein the first filter comprises active and passive elements including an artificial inductance.
4. A tuner as defined in claim 1 wherein the second filter comprises active and passive elements including an artificial inductance.
5. A tuner as defined in claim 4 wherein the first filter comprises active and passive elements including an artificial inductance.
6. A tuner as defined in claim 2 wherein the first and the second filter are integrated on the same semiconductor substrate.
7. A tuner as defined in claim 1 wherein the first filter other than comprises a surface acoustic wave (SAW) filter.
8. A tuner as defined in claim 2 wherein the integrated filter includes the first filter and is integrated within the semiconductor substrate and comprises:
a filter selection signal port for receiving a filter selection signal; and, a plurality of bandpass filters each including a switch controlled by data derived from the filter selection signal for exclusively activating said bandpass filter.
9. A tuner as defined in claim 1 wherein the first filter comprises:
a filter selection signal port for receiving a filter selection signal; and,
a plurality of passbands, each passband being exclusively selectable in response to the filter selection signal designating a corresponding one of the plurality of passbands, each of said passbands being characterized by a bandwidth being sufficiently broad to admit signals in at least one of the plurality of channels with lesser attenuation than other signals.
10. A tuner as defined in claim 1 wherein the one of the first and second filters is integrated within a semiconductor substrate and comprises:
a plurality of lowpass filters and a plurality of highpass filters each comprising:
a filter selection signal port for receiving a filter selection signal; and, a switch responsive to the filter selection signal, whereby one of said highpass filters and one of said lowpass filters are activatable in pairs, some of the filters comprising active and passive elements including an artificial inductance.
11. A method of tuning to a predetermined signal having a predetermined frequency band from within a plurality of channels comprising the steps of:
receiving the plurality of channels;
providing a filter having a bandwidth being sufficiently broad to admit the signal signals in at least one of the plurality of channels with lesser attenuation than other signals, the filter comprising active and passive elements including an artificial inductance;
filtering and amplifying a channel from the plurality of channels using the filter.
12. A method according to claim 11 comprising the step of providing a single integrated circuit for tuning and filtering of the received signal absent external components for filtering thereof.
13. An integrated circuit tuner front end, responsive to a tuner controller signal, for tuning to a designated information modulated signal from a plurality of multiplexed information modulated signals each in a predetermined band of frequencies, comprising:
an input port for receiving the multiplexed information modulated signals;
a first filter for passing all the multiplexed information modulated signals and for attenuating signals that are other than the multiplexed information modulated signals;
a first amplifier for amplifying all the passed multiplexed information modulated signals from the first filter;
a first IF filter for receiving the amplified and passed multiplexed information modulated signals from the first amplifier, the first IF filter for selecting at least one of a designated information modulated signal;
a frequency conversion circuit for receiving a selected at least one of a designated information modulated signal and for converting a baseband frequency thereof; and,
a second IF filter for receiving the converted signal from the frequency conversion circuit and for passing a single designated information modulated signal to an output port thereof, the integrated tuner circuit absent an amplifier circuit electrically between the first IF filter and the second IF filter.
14. An integrated circuit tuner front end according to claim 13 wherein at least one of the first IF filter and second IF filter comprises active and passive elements including an artificial inductance.
15. An integrated circuit tuner front end according to claim 14 wherein at least two of the first filter and first IF filter and second IF filter comprise active and passive elements including an artificial inductance.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US12/711,815 US20100149431A1 (en) | 2002-01-25 | 2010-02-24 | Active Inductor Circuits for Filtering in a Cable Tuner Circuit |
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US35101102P | 2002-01-25 | 2002-01-25 | |
US10/349,938 US7756500B1 (en) | 2002-01-25 | 2003-01-24 | Active inductor circuits for filtering in a cable tuner circuit |
US12/711,815 US20100149431A1 (en) | 2002-01-25 | 2010-02-24 | Active Inductor Circuits for Filtering in a Cable Tuner Circuit |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/349,938 Continuation US7756500B1 (en) | 2002-01-25 | 2003-01-24 | Active inductor circuits for filtering in a cable tuner circuit |
Publications (1)
Publication Number | Publication Date |
---|---|
US20100149431A1 true US20100149431A1 (en) | 2010-06-17 |
Family
ID=42240090
Family Applications (4)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/349,931 Expired - Fee Related US7187913B1 (en) | 2002-01-25 | 2003-01-24 | Integrated circuit tuner with broad tuning range |
US10/349,938 Expired - Fee Related US7756500B1 (en) | 2002-01-25 | 2003-01-24 | Active inductor circuits for filtering in a cable tuner circuit |
US12/711,751 Abandoned US20100149430A1 (en) | 2002-01-25 | 2010-02-24 | Active Inductor Circuits for Filtering in a Cable Tuner Circuit |
US12/711,815 Abandoned US20100149431A1 (en) | 2002-01-25 | 2010-02-24 | Active Inductor Circuits for Filtering in a Cable Tuner Circuit |
Family Applications Before (3)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/349,931 Expired - Fee Related US7187913B1 (en) | 2002-01-25 | 2003-01-24 | Integrated circuit tuner with broad tuning range |
US10/349,938 Expired - Fee Related US7756500B1 (en) | 2002-01-25 | 2003-01-24 | Active inductor circuits for filtering in a cable tuner circuit |
US12/711,751 Abandoned US20100149430A1 (en) | 2002-01-25 | 2010-02-24 | Active Inductor Circuits for Filtering in a Cable Tuner Circuit |
Country Status (1)
Country | Link |
---|---|
US (4) | US7187913B1 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20100178888A1 (en) * | 2009-01-14 | 2010-07-15 | Casio Computer Co., Ltd. | Radio wave receiving apparatus |
US8428531B2 (en) | 2009-05-28 | 2013-04-23 | Casio Computer Co., Ltd. | Radio wave receiver |
US8675078B1 (en) * | 2011-09-30 | 2014-03-18 | Thomson Licensing | Test technique for set-top boxes |
Families Citing this family (54)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7801476B2 (en) * | 2003-09-05 | 2010-09-21 | Gateway, Inc. | Software signal receiver |
US7884886B2 (en) * | 2003-10-27 | 2011-02-08 | Zoran Corporation | Integrated channel filter and method of operation |
US7991379B2 (en) * | 2003-12-19 | 2011-08-02 | Vixs Systems, Inc. | RF transmitter and receiver front-end |
JP3106132U (en) * | 2004-06-23 | 2004-12-16 | アルプス電気株式会社 | Television tuner |
DE102004034274A1 (en) * | 2004-07-15 | 2006-02-09 | Infineon Technologies Ag | Receiver arrangement, in particular for the digital television distribution service and use thereof |
US8160526B2 (en) * | 2004-08-13 | 2012-04-17 | Thomson Licensing | Filter configuration for a receiver of multiple broadcast standard signals |
JP3108712U (en) * | 2004-11-11 | 2005-04-28 | アルプス電気株式会社 | Variable gain amplifier circuit |
US20060128329A1 (en) * | 2004-12-13 | 2006-06-15 | Pieter Van Rooyen | Method and system for receiver front end (RFE) architecture supporting broadcast utilizing a fractional N synthesizer for European, world and US wireless bands |
DE102005007310B3 (en) * | 2004-12-23 | 2006-02-02 | Texas Instruments Deutschland Gmbh | Integrated CMOS-clock-pulse generator, uses oscillator selection circuit to control switches to select oscillator in first or second oscillator block |
WO2006098114A1 (en) * | 2005-03-15 | 2006-09-21 | Sharp Kabushiki Kaisha | Display and television receiver equipped with the display |
US7304533B2 (en) * | 2005-04-15 | 2007-12-04 | Microtune (Texas), L.P. | Integrated channel filter using multiple resonant filters and method of operation |
JP2007036649A (en) * | 2005-07-27 | 2007-02-08 | Orion Denki Kk | Television broadcast receiver |
US7561865B2 (en) * | 2006-09-29 | 2009-07-14 | Silicon Laboratories, Inc. | System and method for determining a resonant frequency in a communications device |
US7941119B2 (en) * | 2006-11-03 | 2011-05-10 | Samsung Electronics Co., Ltd | Signal processing method and apparatus in digital broadcasting apparatus of wireless terminal |
US7813707B2 (en) * | 2006-11-07 | 2010-10-12 | Microtune (Texas), L.P. | High-performance bipolar tuner solution systems and methods |
US7840198B2 (en) | 2006-12-06 | 2010-11-23 | Broadcom Corp. | Method and system for processing signals in a high performance receive chain |
TWI342158B (en) * | 2007-04-09 | 2011-05-11 | Realtek Semiconductor Corp | Multi-system signal receiving apparatus and method thereof |
TWI362843B (en) * | 2007-04-14 | 2012-04-21 | Realtek Semiconductor Corp | A method for receiving signal and apparatus thereof |
US7756504B2 (en) * | 2007-06-29 | 2010-07-13 | Silicon Laboratories Inc. | Rotating harmonic rejection mixer |
US8538366B2 (en) | 2007-06-29 | 2013-09-17 | Silicon Laboratories Inc | Rotating harmonic rejection mixer |
US8260244B2 (en) * | 2007-06-29 | 2012-09-04 | Silicon Laboratories Inc. | Rotating harmonic rejection mixer |
US7860480B2 (en) | 2007-06-29 | 2010-12-28 | Silicon Laboratories Inc. | Method and apparatus for controlling a harmonic rejection mixer |
US8503962B2 (en) * | 2007-06-29 | 2013-08-06 | Silicon Laboratories Inc. | Implementing a rotating harmonic rejection mixer (RHRM) for a TV tuner in an integrated circuit |
US8441580B2 (en) * | 2007-09-27 | 2013-05-14 | Himax Technologies Limited | Method and system for scanning a frequency channel in digital television |
TW200919948A (en) * | 2007-10-18 | 2009-05-01 | Rafael Microelectronics Inc | Tuner with power management means |
CN101453223B (en) * | 2007-11-28 | 2013-09-04 | 瑞昱半导体股份有限公司 | Signal receiving method and related receiving apparatus |
TWI382676B (en) * | 2007-12-28 | 2013-01-11 | Ind Tech Res Inst | Coherent tunable filter apparatus and wireless communication front-end circuit thereof |
KR101454487B1 (en) * | 2008-01-04 | 2014-11-03 | 엘지전자 주식회사 | Tuner |
CN101933324B (en) * | 2008-01-30 | 2013-10-23 | 汤姆森特许公司 | Tuner comprising IF filter with controllable damping stage and receiver comprising respective tuner |
JP5136134B2 (en) * | 2008-03-18 | 2013-02-06 | ソニー株式会社 | BANDPASS FILTER DEVICE, ITS MANUFACTURING METHOD, TELEVISION TUNER, AND TELEVISION RECEIVER |
JP4968145B2 (en) * | 2008-03-31 | 2012-07-04 | ソニー株式会社 | Broadcast signal receiver, reception control method thereof, and IC |
JP4968146B2 (en) * | 2008-03-31 | 2012-07-04 | ソニー株式会社 | Broadcast signal receiver, reception control method thereof, and IC |
JP5029467B2 (en) * | 2008-03-31 | 2012-09-19 | ソニー株式会社 | Electronic device, method for adjusting dispersion of internal components of electronic device, and IC |
JP2009253558A (en) * | 2008-04-03 | 2009-10-29 | Sony Corp | Electronic apparatus, electronic-apparatus adjustment method and integrated circuit |
JP4557086B2 (en) | 2008-06-24 | 2010-10-06 | カシオ計算機株式会社 | Radio wave receiver |
CN101436869B (en) * | 2008-11-27 | 2012-07-04 | 华为技术有限公司 | Equivalent radio frequency belt defect wave filter circuit, radio frequency chip and receiver |
US8411799B1 (en) * | 2009-11-13 | 2013-04-02 | Maxim Integrated Products, Inc. | Receiver with intermediate frequency error correction |
EP2695241B1 (en) | 2011-04-07 | 2021-08-18 | HRL Laboratories, LLC | Tunable impedance surfaces |
EP2695296B1 (en) | 2011-04-07 | 2020-07-15 | HRL Laboratories, LLC | Non-foster circuit |
US20130009720A1 (en) * | 2011-07-06 | 2013-01-10 | Hrl Laboratories, Llc | Wide bandwidth automatic tuning circuit |
US9407239B2 (en) | 2011-07-06 | 2016-08-02 | Hrl Laboratories, Llc | Wide bandwidth automatic tuning circuit |
US8766746B2 (en) | 2011-09-21 | 2014-07-01 | Fujitsu Limited | Active inductor |
US8571512B2 (en) | 2012-01-05 | 2013-10-29 | Silicon Laboratories Inc. | Implementing a passive rotating harmonic rejection mixer (RHRM) for a TV tuner in an integrated circuit |
WO2013131963A1 (en) * | 2012-03-06 | 2013-09-12 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Receiver |
GB2500265B (en) * | 2012-03-16 | 2014-03-05 | Broadcom Corp | Reconfigurable radio frequency circuits and methods of receiving |
US10103445B1 (en) | 2012-06-05 | 2018-10-16 | Hrl Laboratories, Llc | Cavity-backed slot antenna with an active artificial magnetic conductor |
US9705201B2 (en) | 2014-02-24 | 2017-07-11 | Hrl Laboratories, Llc | Cavity-backed artificial magnetic conductor |
US9425769B1 (en) | 2014-07-18 | 2016-08-23 | Hrl Laboratories, Llc | Optically powered and controlled non-foster circuit |
US10193233B1 (en) | 2014-09-17 | 2019-01-29 | Hrl Laboratories, Llc | Linearly polarized active artificial magnetic conductor |
KR20170002903A (en) * | 2015-06-30 | 2017-01-09 | 엘지이노텍 주식회사 | Multiple Mode Wireless Power Transmitting Method and Apparatus Therefor |
US10873387B2 (en) | 2017-02-02 | 2020-12-22 | Wilson Electronics, Llc | Signal booster with spectrally adjacent bands |
WO2018144945A1 (en) * | 2017-02-02 | 2018-08-09 | Wilson Electronics, Llc | Signal booster with spectrally adjacent bands |
JP2019106575A (en) * | 2017-12-08 | 2019-06-27 | ルネサスエレクトロニクス株式会社 | Radio receiver and intermediate frequency signal generation method |
US11024952B1 (en) | 2019-01-25 | 2021-06-01 | Hrl Laboratories, Llc | Broadband dual polarization active artificial magnetic conductor |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6177964B1 (en) * | 1997-08-01 | 2001-01-23 | Microtune, Inc. | Broadband integrated television tuner |
US6472957B1 (en) * | 2001-08-28 | 2002-10-29 | Zenith Electronics Corporation | Low power switchable filter tuner |
Family Cites Families (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4496859A (en) * | 1982-09-30 | 1985-01-29 | Barcus-Berry, Inc. | Notch filter system |
US4571560A (en) * | 1985-05-21 | 1986-02-18 | Zenith Electronics Corporation | Switched bandpass filter |
JP2596488Y2 (en) * | 1992-10-01 | 1999-06-14 | アルプス電気株式会社 | Filter circuit |
US5752179A (en) * | 1995-08-17 | 1998-05-12 | Zenith Electronics Corporation | Selective RF circuit with varactor tuned and switched bandpass filters |
JP3944912B2 (en) * | 1996-04-04 | 2007-07-18 | ソニー株式会社 | Television receiver |
US5745844A (en) * | 1996-10-04 | 1998-04-28 | Motorola, Inc. | Receiver control in a communication device by antenna de-tuning in strong signal conditions, and method therefor |
US6535722B1 (en) * | 1998-07-09 | 2003-03-18 | Sarnoff Corporation | Television tuner employing micro-electro-mechanically-switched tuning matrix |
US6920316B2 (en) * | 2001-09-04 | 2005-07-19 | Freescale Semiconductor, Inc. | High performance integrated circuit regulator with substrate transient suppression |
-
2003
- 2003-01-24 US US10/349,931 patent/US7187913B1/en not_active Expired - Fee Related
- 2003-01-24 US US10/349,938 patent/US7756500B1/en not_active Expired - Fee Related
-
2010
- 2010-02-24 US US12/711,751 patent/US20100149430A1/en not_active Abandoned
- 2010-02-24 US US12/711,815 patent/US20100149431A1/en not_active Abandoned
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6177964B1 (en) * | 1997-08-01 | 2001-01-23 | Microtune, Inc. | Broadband integrated television tuner |
US6472957B1 (en) * | 2001-08-28 | 2002-10-29 | Zenith Electronics Corporation | Low power switchable filter tuner |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20100178888A1 (en) * | 2009-01-14 | 2010-07-15 | Casio Computer Co., Ltd. | Radio wave receiving apparatus |
US8358985B2 (en) | 2009-01-14 | 2013-01-22 | Casio Computer Co., Ltd. | Radio wave receiving apparatus |
US8428531B2 (en) | 2009-05-28 | 2013-04-23 | Casio Computer Co., Ltd. | Radio wave receiver |
US8675078B1 (en) * | 2011-09-30 | 2014-03-18 | Thomson Licensing | Test technique for set-top boxes |
Also Published As
Publication number | Publication date |
---|---|
US20100149430A1 (en) | 2010-06-17 |
US7756500B1 (en) | 2010-07-13 |
US7187913B1 (en) | 2007-03-06 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US7756500B1 (en) | Active inductor circuits for filtering in a cable tuner circuit | |
US8145172B2 (en) | Low-cost receiver using tracking filter | |
US7453527B2 (en) | Highly integrated television tuner on a single microcircuit | |
US7336939B2 (en) | Integrated tracking filters for direct conversion and low-IF single conversion broadband filters | |
US5737035A (en) | Highly integrated television tuner on a single microcircuit | |
US8145170B2 (en) | Low-cost receiver using tracking bandpass filter and lowpass filter | |
US6795128B2 (en) | Television tuner capable of receiving FM broadcast | |
JP3490023B2 (en) | TV signal receiving tuner | |
JP5393703B2 (en) | Tuner with IF filter with controllable attenuation stage and receiver with separate tuner | |
US7738847B2 (en) | Automatic gain control for a tuner | |
US6864924B2 (en) | Television tuner input circuit having satisfactory selection properties at high band reception | |
JPH0730456A (en) | Television tuner | |
US8155609B2 (en) | Switch-able band-tracking input filter for combination tuner | |
JP3101832U (en) | Intermediate frequency circuit | |
JPH09181623A (en) | Electronic tuner |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |
|
AS | Assignment |
Owner name: INTELLECTUAL VENTURES HOLDING 75 LLC, NEVADA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:SIGE SEMICONDUCTOR INC.;REEL/FRAME:026239/0804 Effective date: 20110425 |