WO2007070043A1

WO2007070043A1 - Signal receiving device having multi-stage gain control for multiple control modes

Info

Publication number: WO2007070043A1
Application number: PCT/US2005/045259
Authority: WO
Inventors: Michael Anthony Pugel; Daniel Mark Hutchinson
Original assignee: Thomson Licensing
Priority date: 2005-12-14
Filing date: 2005-12-14
Publication date: 2007-06-21

Abstract

A signal receiving device (100, 200) such as a television signal receiver is capable of receiving signals of various different signal standards including both analog and digital signal standards. According to an exemplary embodiment, the signal receiving device (100, 200) includes a plurality of gain controllable amplifiers (20, 30) which may be connected serially. A controller (55) controls the gain of a first one of the amplifiers (20). A mode switch (60 or 70) controls the gain of the first amplifier (20) for each of the signal standards responsive to a control signal from the controller (55).

Description

SIGNAL RECEIVING DEVICE HAVING MULTI-STAGE GAIN CONTROL FOR

MULTIPLE CONTROL MODES

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention generally relates to signal receiving devices such as television signal receivers, and more particularly, to a signal receiving device having multi-stage gain control with multiple control modes to accommodate different signal standards, including both analog and digital signal standards.

Background Information

Signal receiving devices may be capable of receiving signals of different signal standards and/or formats. For example, devices such as television signal receivers may be capable of receiving signals of both analog signal standards (e.g., NTSC, PAL, SECAM, etc.) and digital signal standards (e.g., ATSC, QAM, QPSK, etc.). In order to accommodate these multiple signal standards, such devices may encounter performance limitations based on the operation of their automatic gain control (AGC) system.

Whether receiving signals of an analog signal standard or of a digital signal standard, the AGC system's function is to optimize the trade-off between signal-to- noise ratio (SNR) and distortion. The system SNR required to produce a noise-free picture is much higher for signals of an analog signal standard than for signals of a digital signal standard; however, signal distortion must be much lower for signals of an digital signal standard than for signals of a analog signal standard. There are several types of signal distortion of concern, all of which originate from amplifier characteristics and the signal levels being processed by those amplifiers. A particularly troublesome distortion in a system receiving digital signals is due to the presence of adjacent channel signals of either analog or digital signal standards. To quantify the distortion producing characteristics of an amplifier, a third order distortion characteristic is often used as a figure of merit, where higher distortion performance is obtained with less third order distortion. Therefore, the optimum AGC characteristics for signals of an analog signal standard will differ considerably from those for signals of a digital signal standard.

Heretofore, signal receiving devices such as television signal receivers have failed to provide an AGC system that adequately supports both analog and digital signal standards and is able to handle a wide range of input signal levels. Accordingly, there is a need for a signal receiving device that addresses the foregoing problems. The present invention addresses these and/or other issues.

SUMMARY OF THE INVENTION

In accordance with an aspect of the present invention, a device for receiving a plurality of signals in which each signal includes information in accordance with a respective signal standard is disclosed. According to an exemplary embodiment, the device comprises a plurality of gain controllable amplifiers connected serially, and a detector operative to detect an output magnitude of the amplifiers. A gain control circuit is operative to control the gain of each of the amplifiers, wherein the gain control circuit is responsive to an output signal of the detector. A controller is operative to detect a plurality of modes by which the gain control circuit affects the gain of each of the amplifiers for each of the signal standards.

In accordance with another aspect of the present invention, a method for providing gain control for a signal receiving device is disclosed. According to an exemplary embodiment, the method comprises steps of providing a plurality of gain controllable amplifiers connected serially, detecting an output magnitude of the amplifiers and generating a first output signal responsive to the detection, determining a signal standard associated with a signal currently being received by the signal receiving device and generating a second output signal responsive to the determination, and controlling the gain of each of the amplifiers responsive to the first and second output signals.

In accordance with another aspect of the present invention, a receiver capable of receiving a plurality of signals in which each of the signals includes information in accordance with a respective signal standard is disclosed. According to an exemplary embodiment, the receiver comprises amplifying means including a plurality of gain controllable amplifiers connected serially. Detecting means detects an output magnitude of the amplifiers and generates a first output signal responsive to the detection. First control means determines which of the signal standards is associated with the signal currently being received by the television signal receiver and generates a second output signal responsive to the determination. Second control means controls the gain of each of the amplifiers responsive to the first and second output signals.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a block diagram of a signal receiving device according to an exemplary embodiment of the present invention; and

FIG. 2 is a flowchart illustrating steps according to an exemplary embodiment of the present invention. The exemplifications set out herein illustrate preferred embodiments of the invention, and such exemplifications are not to be construed as limiting the scope of the invention in any manner. DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings, and more particularly to FIG. 1 , a signal receiving device 100 according to an exemplary embodiment of the present invention is shown. As indicated in FIG. 1, signal receiving device 100 comprises tuning means such as tuner 10, filtering means such as surface acoustic wave

(SAW) filter 20, amplifying means such as amplifier circuit 30, analog-to-digital (AJD) conversion means such as A/D converter 40, processing means such as processor

50, detecting means such as AGC detector 60, digital-to-analog (D/A) conversion means such as D/A converter 70, first control means such as controller 80, and second control means such as AGC circuit 90.

The foregoing elements of signal receiving device 100 may be implemented using integrated circuits (ICs), and one or more elements may be included on a given IC. Moreover, a given element may be included on more than one IC. For clarity of description, certain conventional elements associated with signal receiving device 100 such as certain control signals, power signals and/or other elements may not be shown in FIG. 1. According to an exemplary embodiment, signal receiving device 100 of FIG. 1 represents a portion of a television signal receiver capable of receiving signals of different signal standards including both analog and digital modulation formats. In practice, however, signal receiving device 100 may be implemented as any type of signal receiving device capable of receiving signals of different signal standards.

Tuner 10 is operative to perform a signal tuning function. According to an exemplary embodiment, tuner 10 receives a radio frequency (RF) signal from a signal source such as a terrestrial, cable, satellite, internet and/or other signal source, and performs the signal tuning function by filtering and frequency down converting (i.e., single or multiple stage down conversion) the RF signal to thereby generate an intermediate frequency (IF) signal. The RF and IF signals may include audio, video and/or data content, and may be of an analog signal standard (e.g., NTSC, PAL, SECAM, etc.) and/or a digital signal standard (e.g., ATSC, QAM, QPSK, etc.). Also according to an exemplary embodiment, tuner 10 receives an analog RF AGC signal from D/A converter 70 which enables an RF AGC function.

SAW filter 20 is operative to filter the IF signal provided from tuner 10 to thereby generate a filtered IF signal (e.g., as differential signals). According to an exemplary embodiment, SAW filter 20 includes one or more individual SAW filters which remove a substantial portion of the undesired, adjacent channel energy from the IF signal provided from tuner 10 to generate the filtered IF signal.

Amplifier circuit 30 is operative to amplify the filtered IF signal provided from SAW filter 20 to thereby generate an amplified IF signal. According to an exemplary embodiment, amplifier circuit 30 includes a plurality of serially connected amplifiers shown in FIG. 1 as amplifiers 32, 34 and 36. The number of individual amplifiers included in amplifier circuit 30 is a matter of design choice. Amplifiers 32, 34 and 36 are each capable of providing a predetermined amount of maximum signal gain (e.g., 20 dBm, etc.) and have a predetermined gain range (e.g., 20 dBm, etc.). In order to provide optimal noise and distortion performance, each amplifier 32, 34 and 36 has different noise and distortion performance evidenced for example by their respective noise figures and third order distortion figure of merit. According to an exemplary embodiment, amplifiers 32, 34 and 36 are arranged sequentially based on their respective noise and distortion performance, with amplifier 32 having the lowest noise figure (NF) and highest probability for distortion at larger signal levels and amplifier 36 having the highest NF and the lowest distortion at larger signal levels. The NF and distortion of amplifier 34 are between the NFs and distortion characteristics of amplifiers 32 and 36, respectively. As will be described in greater detail later herein, the gain of each amplifier 32, 34 and 36 is individually controlled via gain control signals provided from AGC circuit 90, and the gain reduction of each amplifier as a function of input signal level is due to operation of the AGC system. The AGC system is optimizaton to facilitate improved signal reception of signals of both analog and digital signal standards.

A/D converter 40 is operative to convert the amplified IF signal provided from amplifier circuit 30 from an analog format to a digital format to thereby generate a digital IF signal which represents a digital version of the amplified IF signal provided from amplifier circuit 30.

Processor 50 is operative to perform various digital processing functions. According to an exemplary embodiment, processor 50 performs a demodulation function, and is capable of demodulating signals of different signal standards including analog signal standards (e.g., NTSC, PAL, SECAM, etc.) and digital signal standards (e.g., ATSC, QAM, QPSK, etc.). Once processor 50 begins to properly demodulate the digital IF signal provided from A/D converter 40, it provides an output signal to controller 80 that indicates the particular signal standard associated with that digital IF signal. Processor 50 may also be operative to perform other processing functions. As indicated in FIG. 1 , output signals from processor 50 may be provided for further processing.

AGC detector 60 is operative to perform an AGC detection function.

According to an exemplary embodiment, AGC detector 60 detects the magnitude of the digital IF signal output from A/D converter 40, and generates digital RF AGC and IF AGC signals responsive to the detected magnitude.

D/A converter 70 is operative to convert the digital RF AGC and IF AGC signals provided from AGC detector 60 from a digital format to an analog format to thereby generate analog RF AGC and IF AGC signals. According to an exemplary embodiment, D/A converter 70 provides the analog RF AGC signal to tuner 10, and provides the analog IF AGC signal to AGC circuit 90. Controller 80 is operative to perform various control functions. According to an exemplary embodiment, controller 80 receives the output signal from processor 50 that indicates the particular signal standard associated with the digital IF signal provided from A/D converter 40. In this manner, controller 80 can detect the particular signal standard associated with a currently received signal. According to another exemplary embodiment, controller 80 may detect the particular signal standard associated with a currently received signal independently of the output signal from processor 50. For example, controller 80 may include a memory, or access to a memory (not shown in FIG. 1), which stores data indicating which channels correspond to which signal standards. In this manner, controller 80 can detect the particular signal standard associated with a currently received signal responsive to a user channel selection input. Regardless of the detection technique employed, controller 80 provides a control signal to AGC circuit 90 that indicates the particular signal standard associated with the currently received signal. Controller 80 may also provide control signals to tuner 10 that change the RF AGC threshold (i.e., the output level of tuner 10 where RF gain reduction begins) based on the particular signal standard associated with the currently received signal. Controller 80 also provides control signals to tuner 10 responsive to user channel selection inputs to thereby effectuate a channel change function.

AGC circuit 90 is operative to perform an AGC function. In general, the AGC function of signal receiving device 100 is performed to provide a relatively constant signal level input to A/D converter 40 and processor 50 given a potentially wide signal level variation at the input to tuner 10. According to an exemplary embodiment, AGC circuit 90 performs the AGC function by providing gain control signals to amplifiers 32, 34 and 36 of amplifier circuit 30 responsive to the analog IF AGC signal provided from D/A converter 70 that indicates the signal level of the currently received signal, and the control signal provided from controller 80 that indicates the particular signal standard associated with the currently received signal. Also according to an exemplary embodiment, AGC circuit 90 includes internal switching means (not shown in FIG. 1) that enables it to provide gain control signals to amplifiers 32, 34 and 36 in a manner that is sequenced as a function of input signal level, and whether the currently received signal is of an analog signal standard (e.g., NTSC, PAL, SECAM, etc.) or a digital signal standard (e.g., ATSC, QAM, QPSK, etc.). According to this exemplary embodiment, AGC circuit 90 provides gain control signals to control (i.e., reduce) the gains of amplifiers 32, 34 and 36 for analog and digital control modes as indicated in Table 1 below.

Table 1

As indicated in Table 1 above, the gain control sequence of amplifiers 32, 34 and 36 varies based on the signal level range of the currently received signal and whether the currently received signal is of an analog signal standard (e.g., NTSC, PAL, SECAM, etc.) or a digital signal standard (e.g., ATSC₁ QAM, QPSK, etc.). According to an exemplary embodiment, signal level range 1 is from -80 dBm to -65 dBm, signal level range 2 is from less than -65 dBm to -57 dBm, signal level range 3 is from less than -57 dBm to -43 dBm, signal level range 4 is from less than -43 dBm to -35 dBm, and signal level range 5 is from less than -35 dBm to -20 dBm. These signal level ranges are exemplary only, and other signal level ranges may also be employed as a matter of design choice.

According to the exemplary embodiment represented in Table 1 , if the currently received signal is of an analog signal standard (i.e., analog control mode), gain control is performed by reducing the gain of amplifier 36 and maintaining amplifiers 32 and 34 at maximum gain, while the currently received signal is in signal level range 1. When the currently received analog standard signal is in signal level range 2, the gains of amplifiers 34 and 36 are reduced and amplifier 32 is held at maximum gain.The gain of amplifier 34 is reduced, amplifier 32 is maintained at maximum gain and amplifier 36 is kept at minimum gain while the currently received signal is in signal level range 3. As the signal is increased to signal level 4 the gain of amplifiers 32 and 34 is reduced and amplifier 36 is held at minimum. In signal level range 5, amplifiers 34 and 36 are held at minimum, while reducing the gain of amplifier 32. This sequence of gain control is particularly advantageous for signals of an analog signal standard since it tends to optimize the system SNR.

Conversely, if the currently received signal is of a digital signal standard (i.e., digital control mode), gain control is performed by reducing the gain of amplifier 32 amplifiers 34, 36 at maximum gain) while the currently received signal is in signal level range 1 , reducing the gains of amplifiers 32 and 34 while the currently received signal is in signal level range 2 (amplifier 36 at maximum gain), reducing the gain of amplifier 34 (with amplifier 32 is minimum and amplifier 36 gain is maximum) while the currently received signal is in signal level range 3, reducing the gains of amplifiers 34 and 36 (with amplifier 32 at minimum gain) while the currently received signal is in signal level range 4, and reducing the gain of amplifier 36 (amplifiers 32 and 34 at minimum gain) while the currently received signal is in signal level range 5. This sequence of gain control versus input signal level is particularly advantageous for signals of a digital signal standard since it lowers the input levels to amplifiers 34 and 36, thus providing more headroom against overload, and thus lower distortion, from strong undesired adjacent channels.

In Table 1 above, it is assumed that a given amplifier 32, 34 and/or 36 provides its maximum level of amplification unless its gain is reduced by gain control signals from AGC circuit 90. Also in Table 1 , the relative degree of gain reduction applied to each amplifier 32, 34 and 36 when the gain of more than one amplifier 32, 34 and 36 is controlled during a given signal level range is a matter of design choice. Moreover, gain control sequences other than those expressly shown in Table 1 may also be employed according to principles of the present invention. In the aforementioned manner, the gains of amplifiers 32, 34 and 36 are individually controlled via gain control signals provided from AGC circuit 90 to facilitate improved signal reception of signals of both analog and digital signal standards.

Referring now to FIG. 2, a flowchart 200 illustrating steps according to an exemplary embodiment of the present invention is shown. In particular, the steps of FIG. 2 represent a signal processing technique using multi-stage gain control for multiple control modes according to principles of the present invention. For purposes of example and explanation, the steps of FIG. 2 will be described with reference to signal receiving device 100 of FIG. 1. The steps of FIG. 2 are merely exemplary, and are not intended to limit the present invention in any manner.

At step 210, signal receiving device 100 tunes an RF signal and thereby generates a resultant IF signal. According to an exemplary embodiment, tuner 10 receives the RF signal from a signal source such as a terrestrial, cable, satellite, internet and/or other signal source and performs a signal tuning function by filtering and frequency down converting (i.e., single or multiple stage down conversion) the RF signal to thereby generate the IF signal at step 210. The RF and IF signals may include audio, video and/or data content, and may be of an analog signal standard (e.g., NTSC, PAL, SECAM, etc.) and/or a digital signal standard (e.g., ATSC₁ QAM, QPSK, etc.). Also according to an exemplary embodiment, tuner 10 performs the signal gain control function at step 210 responsive to the analog RF AGC signal provided from D/A converter 70.

At step 220, signal receiving device 100 filters the IF signal generated at step

210 to thereby generate a filtered IF signal. According to an exemplary embodiment, SAW filter 20 removes a substantial portion of the undesired, adjacent channel energy from the IF signal provided from tuner 10 to thereby generate the filtered IF signal (e.g., as differential signals) at step 220.

At step 230, signal receiving device 100 amplifies the filtered IF signal generated at step 220 to thereby generate an amplified IF signal. According to an exemplary embodiment, amplifier circuit 30 amplifies the filtered IF signal via serially connected amplifiers 32, 34 and 36 based on gain control signals provided via AGC circuit 90. Further details of this operation of AGC circuit 90 will be provided later herein with reference to step 260.

At step 240, signal receiving device 100 digitizes the amplified IF signal generated at step 230 and detects the magnitude of the resultant digital IF signal. According to an exemplary embodiment, A/D converter 40 digitizes the amplified IF signal provided from amplifier circuit 30 to generate a digital IF signal, and AGC detector 60 detects the magnitude of this digital IF signal at step 240. AGC detector 60 then provides a digital IF AGC signal to D/A converter 70 responsive to this detection. D/A converter 70 converts the digital IF AGC signal to an analog format and provides the resultant analog IF AGC signal to AGC circuit 90.

At step 250, signal receiving device 100 determines the signal standard associated with the currently received signal. According to an exemplary embodiment, controller 80 may determine the signal standard at step 250 based on an output signal from processor 50 that indicates the particular signal standard associated with the digital IF signal provided from A/D converter 40. According to another exemplary embodiment, controller 80 may determine the signal standard at step 250 responsive to a user channel selection input by accessing a memory which stores data indicating which channels correspond to which signal standards. Regardless of the detection technique employed, controller 80 provides a control signal to AGC circuit 90 that indicates the particular signal standard associated with the currently received signal. At step 260, signal receiving device 100 controls the gain of amplifiers 32, 34 and 36 of amplifier circuit 30 based on the magnitude of the digitized IF signal detected at step 240 and the signal standard determined at step 250. According to an exemplary embodiment, AGC circuit 90 provides gain control signals to amplifiers 32, 34 and 36 at step 260 responsive to the analog IF AGC signal provided from D/A converter 70 that indicates the signal level of the currently received signal, and the control signal provided from controller 80 that indicates the particular signal standard associated with the currently received signal. According to this exemplary embodiment, AGC circuit 90 provides gain control signals to amplifiers 32, 34 and 36 in a sequenced manner based on the signal level range of the currently received signal, and whether the currently received signal is of an analog signal standard (e.g., NTSC, PAL, SECAM, etc.) or a digital signal standard (e.g., ATSC, QAM, QPSK, etc.). In particular, gain control signals may be provided to amplifiers 32, 34 and 36 in a first control sequence if the currently received signal is of an analog signal standard, and in a second control sequence if the currently received signal is of a digital signal standard. Table 1 herein shows an example of two sequences that may be used for analog and digital signal standards, although variations of these sequences may also be employed in accordance with principles of the present invention.

As described herein, the present invention provides a signal receiving device having multi-stage gain control with multiple control modes to accommodate different signal standards, including both analog and digital signal standards. The present invention may be applicable to various signal receiving devices, either with or without an integral display device. Accordingly, the phrase "television signal receiver" as used herein may refer to devices, systems or apparatus including, but not limited to, television sets, computers or monitors that include an integral display device, and devices, systems or apparatus such as set-top boxes, video cassette recorders (VCRs), digital versatile disk (DVD) players, video game boxes, personal video recorders (PVRs), computers or other devices that may not include an integral display device.

While this invention has been described as having a preferred design, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.

Claims

WHAT IS CLAIMED IS:

1. A device (100) for receiving a plurality of signals, wherein each said signal includes information in accordance with a respective signal standard, said device (100) comprising: a plurality of amplifiers (32, 34, 36), said plurality of amplifiers being gain controllable; a gain control circuit (90) for controlling the gain of each of said amplifiers (32, 34, 36); and a controller (80) operative to detect a plurality of modes by which said gain control circuit (90) affects the gain of each of said amplifiers (32, 34, 36) for each of said signal standards.

2. The device (100) of claim 1 , wherein said gain control circuit (90) controls the gain of each of said amplifiers (32, 34, 36) in a first control sequence when receiving an analog signal standard and a second control sequence when receiving a digital signal standard.

3. The device (100) of claim 1 , wherein said plurality of amplifiers are connected serially.

4. The device (100) of claim 3, wherein: said amplifiers include first, second and third amplifiers (32, 34, 36); said gain control circuit (90) controls the gain of said amplifiers (32, 34, 36) in a first control sequence when amplifying an analog signal standard and a second control sequence when amplifying a digital signal standard; said first control sequence controlling the gain of said third amplifier (36) at a relatively lower input signal level and controlling the gain of said first amplifier (32) at a relatively higher input signal level; said second control sequence controlling the gain of said first amplifier (32) at a relatively lower input signal level and controlling the gain of said third amplifier (36) at a relatively higher input signal level; and said first amplifier (32) provides at least one of lower noise performance and lower distortion performance than said third amplifier (36).

5. The device (100) of claim 1 , further comprising: a tuner (10) for tuning an RF signal and generating an IF signal; a filter (20) for filtering said IF signal and generating a filtered IF signal; a detector (60) for generating a magnitude representative signal responsive to an output magnitude of said amplifiers (32, 34, 36) and communicating said magnitude responsive signal to said gain control circuit (90); and wherein said amplifiers (32, 34, 36) amplify said filtered IF signal responsive to control signals from said gain control circuit (90).

6. The device (100) of claim 5, wherein said detector (60) provides output signals for enabling a gain control function of said tuner (10).

7. A method (200), comprising steps of: providing a plurality of amplifiers said plurality of amplifiers being gain controllable; determining a signal standard associated with a signal currently being received by said signal receiving device and generating an output signal responsive to said determination (250); and controlling the gain of each of said amplifiers responsive to said output signal (260).

8. The method (200) of claim 7, wherein said controlling step (260) includes controlling the gain of each of said amplifiers in a first control sequence if said determination indicates an analog signal standard and controlling the gain of each of said amplifiers in a second control sequence if said determination indicates a digital signal standard.

9. The method (200) of claim 7, wherein said plurality of amplifiers is connected serially.

10. The method (200) of claim 9, wherein: said amplifiers include first, second and third amplifiers; said controlling step (260) includes controlling the gain of each of said amplifiers in a first control sequence if said determination indicates an analog signal standard and controlling the gain of each of said amplifiers in a second control sequence if said determination indicates a digital signal standard; said first control sequence controlling the gain of said third amplifier at a relatively lower input signal level and controlling the gain of said first amplifier at a relatively higher input signal level; said second control sequence controlling the gain of said first amplifier at a relatively lower input signal level and controlling the gain of said third amplifier at a relatively higher input signal level; and said first amplifier provides at least one of lower noise performance and lower distortion performance than said third amplifier.

11. The method (200) of claim 7, further comprising steps of: tuning an RF signal to generate an IF signal (210); filtering said IF signal to generate a filtered IF signal (220); detecting an output magnitude of said amplifiers (32, 34, 36) and generating a magnitude representative signal responsive to said detection (240); and wherein said amplifiers amplify said filtered IF signal responsive to said magnitude representative signal provided during said controlling step (260).

12. The method (200) of claim 11 , further comprising a step of providing a tuner controlling output signal for enabling gain control function during said tuning step (210).

13. A receiver (100) capable of receiving a plurality of signals, wherein each said signal includes information in accordance with a respective signal standard, said receiver (100) comprising: amplifying means (30) including a plurality of amplifiers (32, 34, 36), said plurality of amplifiers being gain controllable; first control means (80) for determining which of said signal standards is associated with a signal currently being received by said television signal receiver (100) and generating a signal standard representative signal responsive to said determination; and second control means (90) for controlling the gain of each of said amplifiers (32, 34, 36) responsive to said signal standard representative signal.

14. The receiver (100) of claim 13, wherein said second control means (90) controls the gain of each of said amplifiers (32, 34, 36) in a first control sequence when receiving an analog signal standard and a second control sequence when receiving a digital signal standard.

15. The receiver (100) of claim 13, wherein said gain amplifiers are connected serially.

16. The receiver (100) of claim 15, wherein: said amplifiers include first, second and third amplifiers (32, 34, 36); said second control means (90) controls the gain of said amplifiers (32, 34, 36) in a first control sequence for an analog signal standard and a second control sequence for a digital signal standard; said first control sequence controlling the gain of said third amplifier (36) at a relatively lower input signal level and controlling the gain of said first amplifier (32) at a relatively higher input signal level; said second control sequence controlling the gain of said first amplifier (32) at a relatively lower input signal level and controlling the gain of said third amplifier (36) at a relatively higher input signal level; and said first amplifier (32) provides at least one of lower noise performance and lower distortion performance than said third amplifier (36).

17. The receiver (100) of claim 13, further comprising: tuning means (10) for tuning an RF signal and generating an IF signal; filtering means (20) for filtering said IF signal and generating a filtered IF signal; detecting means (60) for detecting an output magnitude of said amplifiers (32,34,36) and generating an output magnitude representative signal responsive to said detection; and wherein said amplifiers (32, 34, 36) amplify said filtered IF signal responsive to control signals from said detecting means (60).

18. The receiver (100) of claim 17, further comprising detecting means (60) providing a tuner gain control signal for enabling a gain control function of said tuning means (10).