(19) United States
`(12) Patent Application Publication (10) Pub. No.: US 2004/0031064 A1
`(43) Pub. Date: Feb. 12, 2004
`
`Lindstrom et al.
`
`US 20040031064A1
`
`(54) CABLE RECEIVER HAVING IN-BAND AND
`OUT-OF-BAND TUNERS
`
`(21) Appl. No.:
`
`10/214,960
`
`(75)
`
`Inventors: Mats Lindstrom, San Diego, CA (US);
`Glenn W. Eswein, Branchburg, NJ
`(US); Abdolreza Shafie, San Diego,
`CA (US); Mike A. Ploof, San Diego,
`CA (US); Ryuji Maeda, San Diego, CA
`(US); Manjit S. Gill, San Diego, CA
`(US); Eileen Carlson, San Diego, CA
`(US); Anthony R. Simon, San Diego,
`CA (US)
`
`Correspondence Address:
`PROCOPIO, CORY, HARGREAVES &
`SAVITCH LLP
`530 B STREET
`SUITE 2100
`
`SAN DIEGO, CA 92101 (US)
`
`(73) Assignee: Conexant Systems, Inc.
`
`(22)
`
`Filed:
`
`Aug. 8, 2002
`
`Publication Classification
`
`Int. Cl.7 ....................................................... H04N 7/16
`(51)
`(52) US. Cl.
`........................... 725/150; 725/151; 725/146
`
`(57)
`
`ABSTRACT
`
`Acable television receiver includes in-band and out-of—band
`
`tuners integrated on a single IC. A mode controller deter-
`mines whether an out-of—band signal is being received and
`powers the out-of—band tuner off when no out-of—band signal
`is present. A signal divider divides the signals between the
`in-band and out-of—band tuners and may be an asymmetric
`coupler in order to provide a higher power signal to the
`in-band tuner and a lower power signal to the out-of—band
`tuner.
`
`
`
`(’100
`
`TUNER IC
`
`
`
`102
`
`» IN—BAND /
`>
`TUNER
`
`
`
`W, ,
`
`, W
`
`
`
`101/
`
`(104
`
`OUT-OF—BAND
`TUNER
`
`
`
`
`
`
`
`
`
`
`|PR2020-00200
`
`Apple Inc. EX1008 Page 1
`
`
`
`
`”1“
`fiCABLE gig ,
`
`108
`
`107
`
`/
`
`106
`
`
`
`
`
`
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`

`

`Patent Application Publication
`
`Feb. 12, 2004 Sheet 1 0f 3
`
`US 2004/0031064 A1
`
`
`
`TUNER IC
`
`
`IN-BAND
`
`TUNER
`
`
`108
`
`106
`
`107
`
`(
`
`
`
`
`
`fibfi
`
`
`OUT—OF—BAND
`TUNER
`
`
`
`110
`
`112
`
`101
`
`Figure 1
`
`BUS
`
`118
`
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`

`Patent Application Publication
`
`Feb. 12, 2004 Sheet 2 0f 3
`
`US 2004/0031064 A1
`
`
`
`
`
`136
`
`140
`
`13{O\b
`
`132
`
`
`
`
`@\
`
`
`
`
`
`%
`%
`
`134
`
`
`
`k
`
`
`
`-
`
`%
`m
`
`142
`
`Figure 3
`
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`Patent Application Publication
`
`Feb. 12, 2004 Sheet 3 0f 3
`
`US 2004/0031064 A1
`
`
`
`IDENTIFY
`
`SIGNAL
`
`152
`
`CHANNEL
`
`
`
`156
`
`
`
`POWER OFF
`008 TUNER
`
`
`008 TUNER
`
`
`POWER ON
`
`Figure 4
`
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`US 2004/0031064 A1
`
`Feb. 12, 2004
`
`CABLE RECEIVER HAVING IN-BAND AND
`OUT-OF-BAND TUNERS
`
`FIELD OF THE INVENTION
`
`[0001] The present invention relates to a cable television
`receiver and, more particularly, relates to a cable television
`receiver having in-band and out-of-band tuners on a single
`integrated circuit.
`
`BACKGROUND OF THE INVENTION
`
`[0002] The recent advent of subscriber home terminals,
`such as digital set top boxes, has enabled cable operators to
`offer subscribers a wide array of broadband content beyond
`the usual cable television programming. Electronic and
`interactive programming guides can be received and dis-
`played on the subscriber’s television via the set top box.
`Pay-per-view and video-on-demand programming may be
`directly purchased via the subscriber’s interface with the set
`top box. High speed Internet access and email services may
`be provided. Numerous other applications such as interac-
`tive games, IP telephony and videophone services are envi-
`sioned.
`
`In order to support the receipt and display of this
`[0003]
`multitude of broadband content, the set top box receiver
`typically includes at least two separate tuners. Afirst type of
`tuner, designated an “in-band” (IB) tuner, has the primary
`function of receiving and tuning cable television channels.
`Each channel typically has a fixed width of 6 or 8 MHZ and
`is located in the 50-850 MHZ frequency band. Asecond type
`of tuner, designated an “out-of—band” (OOB) tuner is used to
`receive data and digital content. This content may include
`programming guides, video-on-demand and pay-per-view
`programming, Internet data and so on. The presence of
`multiple tuners permits simultaneous display of cable tele-
`vision programming along with other digital content. Inter-
`net data received over the out-of-band tuner may be dis-
`played on one portion of the television display, for example,
`while a selected television channel is displayed on another
`portion of the display.
`
`[0004] Modern subscriber home terminals employ sepa-
`rate out-of-band and in-band tuners in order to receive both
`
`in-band and out-of-band channels. These separate tuners are
`a costly part of such receivers. Cost advantages could be
`obtained by combining the in-band and out-of-band tuner
`functionality on a single integrated circuit.
`
`SUMMARY OF THE INVENTION
`
`[0005] The present invention provides a receiver having
`an in-band tuner and an out-of-band tuner integrated on a
`single IC.
`In one implementation of the invention,
`the
`receiver is a cable television receiver and a mode controller
`
`is provided for powering the out-of-band tuner on when an
`out-of-band signal is present and powering the out-of-band
`tuner off when no out-of-band signal is present. In a further
`implementation, a signal divider is provided to divide the
`received RF signal either symmetrically or asymmetrically
`between the two tuners.
`
`In another embodiment of the invention, a cable set
`[0006]
`top box is provided. The set top box includes an in-band
`tuner and an out-of-band tuner integrated on a single IC. A
`mode controller powers the out-of-band tuner on when an
`
`input RF signal on an out-of-band channel is received, and
`powers the out-of-band tuner off when an input RF signal on
`an out-of-band channel is not received. In one implementa-
`tion, a coupler divides the input RF signal asymmetrically
`between the in-band tuner and the out-of-band tuner, pro-
`viding a relatively higher power signal to the in-band tuner
`and a relatively lower power signal to the out-of-band tuner.
`
`[0007] The present invention also provides a method for
`tuning in-band and out-of-band cable channels on a single
`IC. An input RF signal is received and provided to both an
`in-band and an out-of-band tuner. If the input signal is on an
`out-of-band channel, the out-of-band tuner is powered on
`and, if the input signal is not on an out-of-band channel, the
`out-of-band tuner is powered off.
`
`[0008] A further embodiment of the invention is a cable
`television receiver having in-band and out-of-band tuning
`means. Mode control means powers the out-of-band tuning
`means on when RF signals on out-of-band channels are
`received, and powers the out-of-band tuning means off when
`RF signals on the out-of-band channels are not received.
`Signal divider means divides the RF signals between the
`in-band tuning means and the out-of-band tuning means.
`
`[0009] Other systems, methods, features and advantages
`of the invention will be or will become apparent to one with
`skill in the art upon examination of the following figures and
`detailed description. It is intended that all such additional
`systems, methods,
`features and advantages be included
`within this description, be within the scope of the invention,
`and be protected by the accompanying claims.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`[0010] The components in the figures are not necessarily
`to scale, emphasis instead being placed upon illustrating the
`principles of the invention. In the figures, like reference
`numerals designate corresponding parts throughout the dif-
`ferent views.
`
`[0011] FIG. 1 is a block diagram illustrates a tuner IC
`having integrated in-band and out-of-band tuners according
`to the present invention.
`
`[0012] FIG. 2 is a schematic diagram of a typical single-
`conversion tuner architecture.
`
`[0013] FIG. 3 is a schematic diagram of a typical dual-
`conversion tuner architecture.
`
`[0014] FIG. 4 is a flow chart illustrating a method for
`switching a tuner between in-band and out-of-band modes
`according to the present invention.
`
`DETAILED DESCRIPTION
`
`[0015] FIG. 1 is a block diagram of a first embodiment of
`the present invention. Tuner integrated circuit (IC) 100 is
`integrated on a single semiconductor chip 101 and com-
`prises an in-band (IB) tuner 102 and an out-of-band (OOB)
`tuner 104. In one implementation, tuner IC 100 is contained
`in a subscriber home terminal such as a cable set top box.
`Functionally, tuner IC 100 is a single component or module
`mountable on a printed circuit board with its signal inputs
`and outputs coupled to the appropriate signal lines within the
`set top box or other receiving system in which it is incor-
`porated. Tuners 102 and 104 are appropriately isolated from
`each other by being placed as remotely as feasible from each
`
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`US 2004/0031064 A1
`
`Feb. 12, 2004
`
`other on chip 101 and/or by use of an appropriate isolation
`structure such as a guard ring or trench.
`
`In-band tuner 102 is used primarily to receive and
`[0016]
`downconvert RF signals containing cable TV channels to an
`intermediate frequency (IF). In-band tuner 102 may also
`receive supplemental data or digital content, such as pro-
`gramming guides and information. The in-band channels are
`typically in the 50-850 MHZ frequency range, and within
`that range, each channel typically occupies a fixed frequency
`band of 6 or 8 MHZ. It may have a single-conversion (FIG.
`2), dual-conversion (FIG. 3) or other architecture, as is
`appropriate to the particular implementation. Where pos-
`sible, a single-conversion architecture is preferred as com-
`ponent count and costs are reduced.
`
`[0017] Out-of—band tuner 104 is used primarily to receive
`and downconvert narrowband data and digital signals to an
`intermediate frequency (IF). The out-of-band channels
`received by tuner 104 are typically located in the 70-130
`MHZ frequency range and, within that range, each channel
`occupies a relatively narrower frequency band of 3 MHZ or
`less. Examples of the types of signals that may be carried on
`the out-of-band channels received by tuner 104 include, but
`are not
`limited to, Internet data, video-on-demand and
`pay-per-view programming,
`interactive
`programming
`guides, interactive games and IP telephony and videophone
`signals. As with in-band tuner 102, tuner 104 may use any
`architecture that is appropriate to the particular application,
`including single-conversion (FIG. 2) and dual-conversion
`(FIG. 3) architectures. Where possible, a single-conversion
`architecture is preferred as component count and costs are
`reduced.
`
`[0018] RF signals received over input cable line 106 are
`provided to both in-band tuner 102 and out-of-band tuner
`104. Alternatively, tuners 102 and 104 may receive in-band
`and out-of-band signals from other RF signal transmission
`mediums, such as wireless transmission. The input RF signal
`is amplified by LNA 107 and then supplied to signal divider
`108. Signal divider 108 is used to route the input RF signal
`to both tuners. LNA 107 and signal divider 108 may be
`on-chip, as illustrated, or may be off-chip.
`
`In the illustrated embodiment, divider 108 com-
`[0019]
`prises a coupler that divides the power unequally or asym-
`metrically between tuners 102 and 104. Use of a coupler is
`advantageous as the power requirements for tuning out-of-
`band digital signals are less than the power requirements for
`tuning in-band analog broadcast signals. Hence, coupler 108
`may be configured to provide a higher power signal to
`in-band tuner 102 and a lower power signal to out-of-band
`tuner 104. In an alternate embodiment, signal divider 108
`comprises a symmetrical splitter that divides the power of
`the input RF signal equally between tuners 102 and 104.
`
`[0020] The signal directed to out-of-band tuner 104 is first
`routed through band pass filter 110 in order to limit the
`signal provided to tuner 104 to narrowband signals within
`the desired frequency band. In one embodiment, filter 110
`passes signals in the 70-130 MHZ band and rejects all other
`signals. Filter 110 may be located on- or off-chip; however,
`the size of filter 110 may dictate that it be located off-chip.
`
`[0021] Tuner IC 100 also includes a mode controller 112
`coupled to out-of-band tuner 104 for powering out-of-band
`tuner 104 on or off, depending on whether out-of-band
`
`signals are being received. Hence, mode controller 112 will
`typically be coupled to the bias inputs of some or all of the
`components within out-of-band tuner 104, and will reduce
`the bias input current to zero when no out-of-band signal is
`present and set the bias current to an appropriate level when
`an out-of-band signal is present. Mode controller 112 may be
`a part of the mode controller for in-band tuner 102, or may
`be implemented as a separate controller.
`
`In one implementation, mode controller 112 is
`[0022]
`controlled by an off-chip computer, processor or software
`via an interface with bus 118. Bus 118 may have a parallel
`or serial configuration. In one implementation, mode con-
`troller 112 includes internal registers 116 whose values are
`updated via bus 118 depending on whether an out-of-band
`signal is being received. Logic circuitry 114 coupled to
`registers 116 powers the various components (described
`below) of tuner 104 on or off based on the values stored in
`registers 116. This is just one embodiment of an out-of-band
`mode controller; other embodiments are possible and are
`within the scope of this invention.
`
`[0023] As indicated above tuners 102 and 104 may be
`configured with any architecture that is appropriate to the
`particular application. FIG. 2 and FIG. 3 depict two poten-
`tial tuner architectures for tuners 102 and 104: a single-
`conversion tuner 120 and a dual-conversion tuner 130.
`
`[0024] Single-conversion tuner 120 (FIG. 2) comprises
`low noise amplifier (LNA) 122, frequency conversion stage
`124, IF filter 126 and IF amplifier 128. LNA 122 amplifies
`the received RF signal a fixed amount with minimal noise
`amplification. As an alternative to a fixed gain amplifier, a
`variable gain amplifier or a fixed gain amplifier in series with
`a variable gain attenuator may be used. The output of LNA
`122 is coupled to frequency conversion stage 124, which
`comprises a mixer and local oscillator. Frequency conver-
`sion stage generates a signal at an intermediate frequency
`(IF) by mixing the input signal with the local oscillator
`signal. The IF signal is coupled to IF filter 126, which is
`typically a band pass filter that selects a band of channels or
`a single channel. The output of filter 126 is passed to IF AGC
`amplifier 128, which further controls the overall tuner gain.
`The output of amplifier 128 is then subjected to further
`processing and/or filter in a known manner to provide IF
`audio and video signals.
`
`[0025] A direct-conversion tuner, rather than a single-
`conversion tuner, could also be used. A direct-conversion
`tuner would be similar to single-conversion tuner 120, but
`would convert the input RF signal to baseband rather than to
`an intermediate frequency, and would us a low pass filter in
`place of band pass filter 126.
`
`[0026] Dual-conversion tuner 130 (FIG. 3) comprises
`LNA 132, first frequency conversion stage 134, first IF filter
`136, second frequency conversion stage 138, second IF filter
`140 and IF AGC amplifier 142. LNA 132 amplifies the
`received RF signal with minimal noise amplification. The
`output of LNA 132 is coupled to first frequency conversion
`stage 134, which up-converts the input RF signal to a signal
`IF1 at a first intermediate frequency that is typically higher
`than the input RF frequency. The IF1 signal is coupled to
`first IF filter 136, which is typically a band pass filter that
`selects a band of channels or a single channel. The output of
`filter 136 is passed to second frequency conversion stage
`138, which down-converts the IF1 signal to a signal IF2 at
`
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`US 2004/0031064 A1
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`Feb. 12, 2004
`
`a second intermediate frequency that is typically lower than
`the input RF frequency. The output signal IF2 is then passed
`through a second IF filter 140 and IF AGC amplifier 142.
`
`[0027] FIG. 4 illustrates a method 150 for switching
`out-of-band tuner 104 between an on state and an off state
`
`are being
`depending on whether out-of-band signals
`received. In step 152, the incoming signal channel is iden-
`tified. With reference to FIG. 1, step 152 is carried out by
`communication of the signal channel (in-band or out-of-
`band) from bus 118 to mode controller 112, with values
`corresponding to the signal channel type being stored in
`register 116. If an out-of-band signal is not being received
`(step 154), mode controller 112 powers tuner 104 off (step
`156). In one implementation, logic circuitry 114 powers
`tuner 104 off by reducing the input bias current to the
`components of tuner 104 to zero. If an out-of-band signal is
`being received (step 154), mode controller 112 powers tuner
`104 on (step 158). In one implementation, logic circuitry 114
`powers tuner 104 on by setting the input bias current to the
`components of tuner 104 to an appropriate level.
`
`in-
`[0028] While out-of-band tuner 104 is powered on,
`band tuner 102 may also be powered on, permitting simul-
`taneous reception and display of in-band and out-of-band
`signals. Hence, digital content such as Internet data, video-
`on-demand options and the like received via out-of-band
`tuner 104 may be displayed in one portion of the viewable
`area, while broadcast programming received via in-band
`tuner 102 is simultaneously displayed in another portion of
`the viewable area. The incoming signal may be continuously
`monitored, so that out-of-band tuner 104 may be intermit-
`tently powered on and off as need to maximize power
`conservation.
`
`[0029] While various embodiments of the invention have
`been described, it will be apparent to those of ordinary skill
`in the art that many more embodiments and implementations
`are possible that are within the scope of this invention.
`
`What is claimed is:
`
`1. A receiver comprising:
`
`an in-band tuner; and
`
`an out-of-band tuner, wherein the in-band and out-of-band
`tuners are integrated on a single IC.
`2. A receiver as claimed in claim 1, wherein the receiver
`is a cable television receiver.
`
`3. Areceiver as claimed in claim 2 and further comprising
`a mode controller for powering the out-of-band tuner on
`when a signal on an out-of-band channel is received and for
`powering the out-of-band tuner off when a signal on an
`out-of-band channel is not received.
`
`4. A receiver as claimed in claim 3, wherein the mode
`controller is coupled to the bias current input of at least one
`component of the out of band tuner, and wherein the bias
`current input is reduced to zero when no out-of-band signal
`is present and is increased to a positive value when an
`out-of-band signal is present.
`5. A receiver as claimed in claim 4, wherein the mode
`controller comprises logic circuitry coupled to the out-of-
`band tuner; and a register coupled to the logic circuitry and
`storing programmed values appropriate to either power on or
`power off the out-of-band tuner.
`
`6. Areceiver as claimed in claim 2, and further comprising
`a signal divider for dividing an input RF signal between the
`in-band tuner and out-of-band tuner.
`
`7. A receiver as claimed in claim 6, wherein the signal
`divider is a splitter that divides the input RF signal sym-
`metrically between the in-band tuner and out-of-band tuner.
`8. A receiver as claimed in claim 6, wherein the signal
`divider is a coupler that divides the input RF signal asym-
`metrically between the in-band tuner and the out-of-band
`tuner.
`
`9. A receiver as claimed in claim 8, wherein the coupler
`provides a relatively higher power signal to the in-band
`tuner and a relatively lower power signal to the out-of-band
`tuner.
`
`10. A receiver as claimed in claim 6, and further com-
`prising a band pass filter coupled between the signal divider
`and the out-of-band tuner to reject RF signals that are not in
`an out-of-band channel.
`
`11. Aset top box comprising a cable television receiver as
`claimed in claim 2.
`
`12. A cable television receiver comprising:
`
`an in-band tuner and an out-of-band tuner, wherein the
`in-band and out-of-band tuners are integrated on a
`single IC;
`
`a mode controller for powering the out-of-band tuner on
`when an input RF signal on an out-of-band channel is
`received, and for powering the out-of-band tuner off
`when an input RF signal on an out-of-band channel is
`not received; and
`
`a coupler that divides the input RF signal asymmetrically
`between the in-band tuner and the out-of-band tuner,
`providing a relatively higher power signal to the in-
`band tuner and a relatively lower power signal to the
`out-of-band tuner.
`
`13. A method for tuning in-band and out-of-band cable
`channels on a single IC comprising:
`
`receiving an input RF signal;
`
`providing the input RF signal to an in-band tuner and to
`an out-of-band tuner;
`
`detecting whether an input signal is on an out-of-band
`channeh
`
`if the input signal is on an out-of-band channel, powering
`the out-of-band tuner on; and
`
`is not on an out-of-band channel,
`if the input signal
`powering the out-of-band tuner off.
`14. A method as claimed in claim 13, and further com-
`prising the step of dividing the input RF signal into first and
`second signals, wherein the first signal is a signal of rela-
`tively higher power that is provided to the in-band tuner and
`the second signal is a signal of relatively lower power that
`is provided to the out-of-band tuner.
`15. A cable television receiver comprising:
`
`in-band tuning means for tuning RF signals received on
`in-band channels;
`
`out-of-band tuning means for tuning RF signals received
`on out-of-band channels;
`
`mode control means for powering the out-of-band tuning
`means on when RF signals on the out-of-band channels
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`US 2004/0031064 A1
`
`Feb. 12, 2004
`
`are received, and for powering the out-of—band tuning
`means off when RF signals on the out-of—band channels
`are not received; and
`
`signal divider means for dividing the RF signals between
`the in-band tuning means and the out-of—band tuning
`means.
`
`16. A cable television receiver as claimed in claim 15,
`wherein the signal divider means asymmetrically divides the
`RF signals.
`17. A cable television receiver as claimed in claim 16,
`wherein the signal divider means provides a relatively
`higher power signal to the in-band tuner and a relatively
`lower power signal to the out-of—band tuner.
`18. A cable television receiver as claimed in claim 15,
`wherein the signal divider means symmetrically divides the
`RF signals.
`
`19. A method for tuning in-band and out-of—band cable
`frequency channels on a single IC comprising:
`
`a step for receiving an input RF signal;
`
`a step for dividing the input RF signal between an in-band
`tuner and an out-of—band tuner;
`
`a step for powering the out-of—band tuner on if the input
`signal is on an out-of—band channel; and
`
`a step for powering the out-of—band tuner off if the input
`signal is not on an out-of—band channel.
`20. A method as claimed in claim 19, wherein the power
`level of the divided signal provided to the out-of—band tuner
`is lower than the power level of the divided signal provided
`to the in-band tuner.
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