CN1284365C

CN1284365C - Combination tuner for earth and satellite broadcasting

Info

Publication number: CN1284365C
Application number: CNB028076818A
Authority: CN
Inventors: 崔石东
Original assignee: LG Innotek Co Ltd
Current assignee: LG Innotek Co Ltd
Priority date: 2001-04-03
Filing date: 2002-04-02
Publication date: 2006-11-08
Anticipated expiration: 2022-04-02
Also published as: CN1528086A; WO2002082809A1; KR100365359B1; KR20020078482A; EP1380163A4; EP1380163A1

Abstract

Combination-tuner for receiving Ground wave and satellite wave, the tuner comprising: A satellite frequency output part for receiving satellite wave, a ground frequency output part for receiving ground wave, first switching means to input selectively the RF signals which are output through the satellite frequency output part or ground frequency output part by control signals, IF signal forming means for forming IF signals, second switching means to input selectively the IF signals, low pass filters to filter selectively ground wave or satellite wave out of second IF signals which is output though the second switching means.

Description

The combination tuner that is used for ground and satellite broadcasting

Technical field

The present invention relates to a kind of tuner, and relate in particular to a kind of combination tuner that is used for ground and satellite broadcasting, it allows the observer to use single equipment optionally to receive terrestrial broadcasting or satellite broadcasting.

Background technology

Usually, tuner is driven with two kinds of translation types, for example, and single translation type and double conversion type.A single translation type tuner output intermediate frequency (IF) signal.Double conversion type tuner amplifies and synthesizes first intermediate frequency (IF) signal so that an IF conversion of signals is become the 2nd IF signal, carries out simultaneously and detects.These double conversion type tuners are classified as ground EH tunerE H and satellite electric wave tuner again.

Simultaneously, converting broadcast singal to the IF signal, to finish the trace routine of the IF signal that is converted simultaneously be the mode that a kind of quilt generally adopts, thereby improve the selectivity of frequency.

Fig. 1 is the block diagram of traditional double conversion type terrestrial tuner.

With reference to Fig. 1, double conversion type terrestrial tuner 1 comprises AGC (automatic gain controller) 2, tracking filter 3, RF amplifier 4, RF filter 5, the first frequency mixers 6, first local oscillator 7, the one PLL 8, the one IF filters 9, the one IF amplifiers 10, second frequency mixer 11, second local oscillator, 12, the two PLL, 13, the two IF filters 14.

At length, thus even AGC 2 automatic ride gains cause and radio frequency (RF) signal with frequency range of 44 to 860MHz of input is changed in size from antenna, the output of picture signal always is maintained on the constant level.

Tracking filter 3 is removed by what antenna received and is included in noise in the RF signal, and only allows the RF signal corresponding to the expected frequency wave band pass through.

4 pairs of RF signals through tracking filter 3 of RF amplifier amplify.

RF filter 5 is from being selected the RF component of expectation RF amplifier 4 amplifying signals.

First frequency mixer 6 will be in RF filter 5 frequency of oscillation that produces of selecteed RF component and first local oscillator 7 synthesize, thereby export an IF signal.When selecting a channel, first local oscillator 7 produces certain frequency of oscillation and the frequency of oscillation that produces is outputed to first frequency mixer 6 according to the control voltage of a PLL 8.If the backup channel data are arranged inside, a PLL (phase-locked loop) 8 outputs to first local oscillator 7 to control voltage according to external control.

The one IF filter 9 only makes the IF component of the expectation from an IF signal of first frequency mixer, 6 outputs pass through.

10 pairs of IF signals from 9 outputs of first filter of the one IF amplifier amplify.

The oscillation frequency signal that second frequency mixer 11 will be produced by an IF signal and second local oscillator 12 of an IF amplifier 10 amplifications synthesizes, thereby exports the 2nd IF signal.When selecting a channel, second local oscillator 12 relies on the 2nd PLL 13 to produce certain frequency of oscillation, simultaneously the frequency of oscillation that produces is outputed to second frequency mixer 11.If the backup channel data are arranged inside, the 2nd PLL relies on external control that control voltage is outputed to second local oscillator 12.

The 2nd IF filter 14 only allows the signal with desired bandwidth among the 2nd IF signal of second frequency mixer 11 output pass through.

Channel when the selection expectation in the earthwave signal of from antenna (ANT), introducing of aforesaid double conversion type tuner 1, the channel of expectation is selected by a PLL 8 controls, will be by the frequency of oscillation up conversion to IF corresponding to the signal of desired channel with 1038MHz through first frequency mixer 6 and an IF filter 9, simultaneously again by second frequency mixer 11 and the 2nd IF filter 14 to be converted to the IF of final 44MHz by the frequency of oscillation frequency reducing.

Simultaneously, double conversion type satellite electric wave tuner has identical structure with traditional ground EH tunerE H, but in the frequency inverted mode be used for being different from traditional ground EH tunerE H aspect the target frequency of frequency reducing frequency conversion.

Yet, if these traditional double conversion type ground EH tunerE Hs and satellite tuner are applied on the single equipment, just require to apply respectively the tuner separately that is suitable for ground EH tunerE H and satellite electric wave tuner, thereby having any problem aspect the reduction of manufacturing cost.

Simultaneously, continued on the electron waves receiver market of miniaturization because ground EH tunerE H and satellite electric wave tuner use respectively being positioned, thereby volume increases, this is a sizable problem.

Summary of the invention

The present invention is in order to solve aforesaid problem, and purpose is to provide a kind of combination tuner that can receive earthwave and satellite electric wave that is used for ground and satellite broadcasting.

With other advantage, the combination tuner that is used for ground and satellite broadcasting that provides here comprises: the double conversion tuner to achieve these goals, it comprises first antenna, AGC, first amplifier, first low pass filter, first frequency mixer, first local oscillator, a PLL, first band pass filter, second amplifier, second frequency mixer, second local oscillator and the 2nd PLL; The satellite frequency output is used to receive the satellite electric wave and exports the certain frequency signal that satellite electric wave and frequency of oscillation are mixed mutually; First switching device, its control signal conversion of being imported from the outside is to select and to export from the RF signal of first antenna input or the RF signal that uses same AGC to export from the satellite frequency output; The second switch device, it is converted optionally to provide from the 2nd IF signal of second frequency mixer output together in company with first switching device; Second low pass filter is used for only by the earthwave wave band corresponding to the 2nd IF signal of exporting from the second switch device; Simultaneously the 3rd low pass filter only is used for by corresponding to the satellite electric wave audio range frequency from the 2nd IF signal of second switch device output, and wherein this certain frequency is the frequency corresponding to the earthwave wave band.

According to another viewpoint of the present invention, a kind of combination tuner that is used for ground and satellite broadcasting is provided, comprising: the double conversion tuner, it comprises first antenna, AGC, first amplifier, first low pass filter, first frequency mixer, first local oscillator, a PLL, first band pass filter, second amplifier, second frequency mixer, second local oscillator and the 2nd PLL; Be used to the satellite frequency output that receives the satellite electric wave and export the certain frequency signal; First switching device is used for optionally being exported from the 2nd IF signal of second frequency mixer input or the RF signal of exporting from the satellite frequency output by external control signal; Second switch device, itself and first switching device are incorporated into line operate and optionally provide simultaneously from the 2nd IF signal of first switching device output; Second low pass filter is used for only by the earthwave audio range frequency corresponding to the 2nd IF signal of exporting from the second switch device; And the 3rd low pass filter is used for only by the satellite electric wave audio range frequency corresponding to the 2nd IF signal of exporting from the second switch device.

According to another viewpoint of the present invention, a kind of combination tuner that is used for ground and satellite broadcasting is provided, comprising: the ground frequency output that mainly comprises the ground wave antenna that is used to receive earthwave; The satellite frequency output mainly comprises the certain frequency signal that the satellite electric wave antenna that is used to receive the satellite electric wave and output mix the frequency of oscillation and the satellite-signal of satellite electric wave antenna reception mutually; Be used for optionally providing first switching device from the frequency of earthwave output or the output of satellite frequency output; And be formed in the second switch device of the first switching device rear end, and be used for optionally will be being provided to the low pass filter that is fit to earthwave and satellite electric wave through the signal of first switching device, wherein this certain frequency is the frequency corresponding to the earthwave wave band.

Description of drawings

Fig. 1 is the block diagram of the traditional double conversion type terrestrial tuner of expression;

Fig. 2 is the block diagram of a preferred embodiment of the expression combined tuned device that is used for ground and satellite broadcasting according to the present invention; And

Fig. 3 is the block diagram of another preferred embodiment of the expression combined tuned device that is used for ground and satellite broadcasting according to the present invention.

Preferred forms

Hereinafter, with reference to Fig. 2 a preferred embodiment that is used for the combination tuner of ground and satellite broadcasting according to the present invention is described.

Fig. 2 is the block diagram of a preferred embodiment that is used to represent to be used for according to the present invention the combined tuned device of ground and satellite broadcasting.

With reference to Fig. 2, be used for the combination tuner 100 of ground and satellite broadcasting, comprise first antenna (ANT1), second antenna (ANT 2), AGC 101, the first amplifiers 102, first low pass filter 103, first frequency mixer, 104, the first local oscillators, 105, the one PLL 106, first band pass filter 107, second amplifier, 108, the second frequency mixers, 109, the second local oscillators 110, the 2nd PLL 111, three-mixer 112, the three local oscillators 113, the three PLL 114, first switch 115, second switch 116, the second low pass filters 117, and the 3rd low pass filter 118.

In more detail, first antenna (ANT 1) receives corresponding to frequency band at the earthwave in 44 to 860MHz scopes, and second antenna (ANT 2) receives corresponding to frequency band at the satellite electric wave in 950 to 2150MHz scopes.

Three-mixer 112 will synthesize the satellite electric wave with the frequency of oscillation of importing from the 3rd local oscillator 113 from the RF signal of second antenna (ANT 2) input, to export certain intermediate frequency (IF) signal.Preferably has the frequency of 479.5MHz from the IF signal of three-mixer 112 outputs.

The 3rd local oscillator 113 uses from the control voltage of the 3rd PLL 114 inputs that store channel data and produces certain frequency of oscillation, and the frequency of oscillation that produces is outputed to three-mixer 112.The 3rd PLL 114 receives the feedback voltage of the 3rd local oscillator 113, thereby and control voltage is outputed to the 3rd local oscillator 113.

First switch 115 has the fixed terminals " a " that is connected to first antenna (ANT 1) output, is connected to the fixed terminals " b " of three-mixer 112 outputs, and the working end.The working end of first switch 115 is by the external control signal control transformation, so therefore select to output to AGC 101 from the IF signal of three-mixer 112 outputs and with the IF signal of selecting.Simultaneously, first switch 115 is by the QAM or the QPSK control transformation of system, and working end wherein combines with second switch 116 and is changed simultaneously.

Even thereby the working end that AGC 101 is connected to first switch 115 changes with the RF signal magnitude by 115 inputs of first switch of ride gain automatically, also can export with constant by inhibit signal.The RF signal that first amplifier 102 amplifies through AGC 101.Low pass filter 103 is only by the 860MHz in the RF signal that is amplified by first amplifier 102 or be less than the RF signal composition of 860MHz.

The RF signal that first frequency mixer 104 will be selected by first low pass filter 103 with synthesize from the frequency of oscillation of first local oscillator, 105 inputs, export IF signal after being converted to increase RF signal frequently simultaneously to an IF signal with 1038MHz frequency.When selecting a channel, first local oscillator 105 produces frequency of oscillation according to the control voltage that provides from a PLL 106, frequency of oscillation is outputed to first frequency mixer 104.The one PLL 106 receives from the output voltage of first local oscillator, 105 feedbacks and outputs to first local oscillator 105 to provide and to control voltage according to the big wisp of output voltage.

First band pass filter 107 only passes through the frequency according to the wave band of the expectation from first intermediate frequency of first frequency mixer, 104 outputs.Second amplifier 108 is connected to the output of first band pass filter 107 to amplify from the signal of first band pass filter, 107 outputs.

Second frequency mixer will be synthesized by second amplifier 108 an IF signal that amplifies and the frequency of oscillation of importing from second local oscillator 110, have the 2nd IF signal of 45MHz frequency with output.When selecting a channel, second local oscillator 110 produces frequency of oscillation so that the frequency of oscillation that produces is outputed to second frequency mixer 109 according to the control voltage of the 2nd PLL 111.The 2nd PLL 111 receives from the output voltage of second local oscillator, 110 feedbacks and outputs to second local oscillator 110 with the big wisp control voltage according to output voltage.

The working end of second switch 116 is connected to 109 1 outputs of second frequency mixer, and fixed terminals " a " is connected to an input of second low pass filter 117, and fixed terminals " b " is connected to an input of the 3rd low pass filter 118.Second switch is changed optionally the 2nd IF signal from 109 outputs of second frequency mixer is provided to second low pass filter 117 or the 3rd low pass filter 118 according to external control signal.Here, second switch 116 is to change according to the QAM of system or the control of QPSK.

Second low pass filter 117 only is suitable for receiving the frequency of the bandwidth of earthwave by having from second intermediate frequency of second switch 116 output, and the 3rd low pass filter 118 is only by the frequency that is suitable for receiving satellite electric wave wave band that has from second intermediate frequency of second switch 116 outputs.

At length, second low pass filter 117 is only by having the frequency of 10MHz bandwidth, and the 3rd low pass filter is only by having the frequency of 45MHz bandwidth.

Simultaneously, more accurately, bandwidth is to be used to transmit the width that the frequency band of the data that device provides is provided by transmission equipment side.Preferablely be to use SPS (per second symbol rate) to replace bandwidth, but because SPS is similar with bandwidth each other, utilized bandwidth is that it is used in the following description equally for the convenience of describing with precise definition more.

Hereinafter, the work according to a preferred embodiment of the combined tuned device that is used for ground and satellite broadcasting of the present invention specifically describes with reference to Fig. 2.

At first, when requiring to receive the broadcast singal that is used for earthwave, the QAM of system or QPSK couple together the working end and their fixed terminals " a " of first switch 115 and second switch 116 respectively.

Simultaneously, first and

second switches

115 and 116 the initial condition working end that is set to first and

second switches

115 and 116 state that is connected to the fixed terminals " a " of first and

second switches

115 and 116 is allowed to.

The RF signal of introducing by first antenna (ANT 1) is tuning waveform when by first switch 115, AGC 101, first amplifier 102 and first low pass filter 103.Then, when by first frequency mixer 104, the RF signal is increased frequently to first intermediate frequency (1038MHz).By first band pass filter 107, the expected bandwidth frequency that only has from first intermediate frequency of first frequency mixer, 104 outputs is passed through first band pass filter 107.

Then, signal is exaggerated when by second amplifier 108, and is mixed down to second intermediate frequency (45MHz) when by second frequency mixer 109.Then, only has the frequency of 10MHz bandwidth by the second switch 116 and second low pass filter 117.

On the contrary, when requiring to receive the broadcast singal that is used for the satellite electric wave, the QAM of system or QPSK couple together the working end of first and

second switches

115 and 116 and the fixed terminals " b " of first and

second switches

115 and 116.

Then, destroyed when passing through three-mixer 112 by the RF signal that second antenna (ANT 2) is introduced, thus working end and the fixed terminals " b " of the signal that only has a 479.5MHz frequency by first switch 115 is imported into AGC 101.

Thereafter, the signal process increases after frequency step and the frequency reducing step, and the frequency that only has the 45MHz bandwidth of suitable satellite electric wave when second switch 116 is converted is output by the 3rd low pass filter 117.

Thereby, by on single tuner architecture, using many switches and change over switch, optionally be incorporated in the circuit via the ground and the satellite electric wave signal of antenna input separately, carry out trace routine by single structure simultaneously.The bandwidth of ground and satellite electric wave is selected by second frequency mixer 109 by different low pass filter 117 and 118.According to aforesaid structure and the operation of on single tuner architecture, using pair of switches, can produce the effect that receives earthwave and satellite electric wave simultaneously.

With reference to Fig. 3, be used for the combined tuned device 200 of ground and satellite broadcasting, comprise the tenth antenna (ANT 1), AGC 201, the ten amplifiers 202, the ten low pass filters 203, the tenth frequency mixer 204, the tenth local oscillator 205, the ten PLL 206, the ten band pass filters 207, the 20 amplifier 208, the 20 frequency mixer 209, the 20 local oscillators 210, the 20 PLL 211, Ahau line (ANT 2), the 30 frequency mixer 212, the 30 local oscillators 213, the 30 PLL 214, the tenth switch 215, the 20 switch 216, the 20 low pass filters 217, and the 30 low pass filter 218.

At length, the tenth antenna (ANT 1) receives corresponding to 44 earthwaves to 860MHz range frequencies wave band.

Even thereby the working end that AGC 201 is connected to the tenth switch 115 changes with the RF signal magnitude from the tenth antenna (ANT 1) input of ride gain automatically, also can keep picture signal to export with constant.202 pairs of RF signals through AGC 201 of the tenth amplifier amplify.The tenth low pass filter 203 is only by having 860MHz or being less than the RF signal of 860MHz frequency in the RF signal that is amplified by the tenth amplifier 202.

The RF signal that the tenth frequency mixer 204 will be selected by the tenth low pass filter 203 is exported the IF signal that increases behind the frequency simultaneously with synthesize from the frequency of oscillation of the tenth local oscillator 105 inputs the RF signal is increased frequently to the IF of 1038MHz.When selecting a channel, the tenth local oscillator 205 produces frequency of oscillation according to the control voltage that provides from the tenth PLL 206, frequency of oscillation is outputed to the tenth frequency mixer 204.The tenth PLL 206 receives from the output voltage of the tenth local oscillator 205 feedbacks and controls voltage with the size output according to output voltage.

The tenth band pass filter 207 is only by the frequency corresponding to the expectation wave band from first intermediate frequency of the tenth frequency mixer 204 outputs.The 20 amplifier 208 is connected on the output of the tenth band pass filter 207 so that the signal from 208 outputs of the 20 amplifier is amplified.

The 20 frequency mixer 209 will be synthesized by the 20 amplifier 208 an IF signal that amplifies and the frequency of oscillation of importing from the 20 local oscillator 210, with the 2nd IF of output 45MHz.When selecting a channel, the 20 local oscillator 210 produces frequency of oscillation according to the control voltage of the 20 PLL 211, outputs to the 20 frequency mixer 209 with the frequency of oscillation that will produce.The 20 PLL211 reception is controlled voltage from the output voltage of the 20 local oscillator 210 feedbacks with the big young pathbreaker according to output voltage and is outputed to the 20 local oscillator 210.

Simultaneously, Ahau line (ANT 2) receives the satellite electric wave according to 950 frequency ranges that arrive 2150MHz.

The 30 frequency mixer 212 will synthesize from Ahau line (ANT 2) RF signal that receives and the frequency of oscillation of importing from the 30 local oscillator 213, with the intermediate frequency (IF) of exporting a 45MHz.

The 30 local oscillator 213 produces frequency of oscillation according to the control voltage from the 30 PLL 214 inputs, outputs to the 30 frequency mixer 212 with the frequency of oscillation that will produce.The 30 PLL 214 receives from the output voltage of the 30 local oscillator 213 feedbacks and outputs to the 30 local oscillator 213 will control voltage.

The tenth switch 215 has a fixed terminals " a " to be connected to the output of the 20 frequency mixer 209, reaches the output that a fixed terminals " b " is connected to the 30 frequency mixer 212.Said structure by the tenth switch 215, the working end of the tenth switch 215 is by an external control signal control transformation, thereby is output to the 20 switch 216 from the 2nd IF of the 20 frequency mixer 209 outputs or from a selecteed IF of selected while of IF of the 30 frequency mixer 312 outputs.Here, the tenth switch 215 is by the control transformation of the QAM or the QPSK of system, and its working end combines with the 20 switch 216 and is changed.

The 20 switch 216 has the working end that the working end is connected to the tenth switch 215, and fixed terminals " a " is connected to the input of the 20 low pass filter 217, and fixed terminals " b " is connected to the input of the 30 low pass filter 218.The 20 switch 216 relies on external control signal to change optionally will be provided to the 20 low pass filter 217 or the 30 low pass filter 218 from the 2nd IF signal of the 20 frequency mixer 209 outputs or the IF signal of exporting from the 30 frequency mixer 212.Here, the 20 switch 216 is to change according to the QAM of system or the control of QPSK, and especially, the tenth switch 215 combines with the 20 switch 216 and carries out work.

The 20 low pass filter 217 is only by the frequency with 10MHz bandwidth (BW) from second intermediate frequency of the 20 switch 216 outputs, and the 30 low pass filter 218 is only by having from the frequency of the intermediate frequency 45MHz bandwidth of the 20 switch 216 outputs.

Hereinafter, another preferred embodiment that is used for the combined tuned device of ground and satellite broadcasting according to the present invention is described in detail with reference to Fig. 3.

At first, when requiring to receive the broadcast singal that is used for earthwave, the QAM of system or QPSK couple together the working end and their fixed terminals " a " of the tenth switch 215 and the 20 switch 216 respectively.At this moment, the tenth and the 20 switch 215 and 216 initial condition are set to the state that the fixed terminals " a " of the working end of the tenth and the 20 switch 215 and 216 and the tenth and the 20 switch 215 and 216 couples together and are allowed to.

Constitute tuning waveform when then, the RF signal of introducing by the tenth antenna (ANT 1) ought be sequentially via AGC 201, the ten amplifiers 202 and the tenth low pass filter 203.Afterwards, the RF signal after tuning is increased frequently to first intermediate frequency (1038MHz) during through the tenth frequency mixer 204.Then, the tenth band pass filter 207 is only by having the frequency of the expected bandwidth among the tenth intermediate frequency of the tenth frequency mixer 204 output.

Thereafter, this signal is exaggerated when by the 20 amplifier 208, is mixed down to intermediate frequency (45MHz) then when by the 20 frequency mixer 209.Then, only has frequency corresponding to the 10MHz bandwidth of earthwave by the 20 switch 216 and the 20 low pass filter 217.

On the contrary, when requiring to receive the broadcast singal that is used for the satellite electric wave, the QAM of system or QPSK couple together the working end of the tenth and the 20 switch 215 and 216 and the fixed terminals " b " of the tenth and the 20 switch 215 and 216.

Then, destroyed when via the 30 frequency mixer 212 by the RF signal that Ahau line (ANT 2) is introduced, thus working end and the fixed terminals " b " of the signal that only has a 45MHz frequency by the tenth switch 215 outputs to the 20 switch 216.

Because above-mentioned work, filtered by the 30 low pass filter 218 via the IF signal of the 20 switch 216, thereby only have frequency corresponding to the 45MHz bandwidth of satellite electric wave by the 30 low pass filter 217.

Thereby, by on single tuner architecture, using many switches and diverter switch, ground and satellite electric wave signal by antenna input separately optionally are incorporated into circuit, and tuner allows to pass through different low pass filters from the 2nd IF of the 20 frequency mixer output or from the IF that the 30 frequency mixer is exported, thereby earthwave and satellite electric wave can both be received.

Simultaneously, above-mentioned specific embodiment can obtain from other aspects looking back.In other words, tuner comprises ground frequency output, and it is to be used to receive earthwave and element is overlapped in one of received earthwave output, and the satellite frequency output, and it is to be used to receive the satellite electric wave and element is overlapped in one of received satellite electric wave output.Equally, first and second switching devices are included in the tuner, thereby the received signal quilt low pass filter separately of output and satellite frequency output output frequently filters and the signal that is filtered is exported from ground, therefore, and the structure of description tuner that can be whole.

As previously mentioned, according to the combined tuned device that is used for ground and satellite broadcasting of the present invention, earthwave and satellite electric wave can be received by single tuner, thereby manufacturing cost and small product size can reduce.

Industrial applicibility

Provide such as the front, the combination tuner that is used for ground and satellite broadcasting is tied at single tuner Increase a pair of simple switch on the structure, thereby the effect that can receive simultaneously earthwave and satellite electric wave is provided.

Equally, the circuit structure of tuner is simplified to reduce the volume of electric wave reception device, thereby this Bright tuner has been considered the more approaching method in the miniaturization of electric wave reception device.

Further, tuner of the present invention allow by independent radio wave receiver receive simultaneously earthwave and The satellite electric wave, thus manufacturing cost reduced.

Claims

1, a kind of combination tuner that is used for ground and satellite broadcasting comprises:

The double conversion tuner, it comprises first antenna, AGC, first amplifier, first low pass filter, first frequency mixer, first local oscillator, a PLL, band pass filter, second amplifier, second frequency mixer, second local oscillator and the 2nd PLL is characterized in that, also comprise:

The satellite frequency output is used to receive the satellite electric wave and exports the certain frequency signal that satellite electric wave and frequency of oscillation are mixed mutually;

First switching device is changed by the control signal of outside input, to select and to export from the RF signal of first antenna input or the RF signal that uses same AGC to export from the satellite frequency output;

The second switch device is converted together in company with first switching device, optionally to provide from the 2nd IF signal of second frequency mixer output;

Second low pass filter only is used for by corresponding to the frequency from the earthwave wave band of the 2nd IF of second switch device output; And

The 3rd low pass filter only is used for by corresponding to the frequency from the satellite electric wave wave band of the 2nd IF of second switch device output;

Wherein this certain frequency is the frequency corresponding to the earthwave wave band.

2, combination tuner according to claim 1, wherein second low pass filter is by 10MHz or be lower than the signal of 10MHz bandwidth.

3, combination tuner according to claim 1, wherein the 3rd low pass filter is by 45MHz or be lower than the signal of 45MHz bandwidth.

4, combination tuner according to claim 1, wherein the satellite frequency output comprises:

Be used to receive second antenna of satellite electric wave;

Be used for and synthesize to export the three-mixer of certain frequency from the RF signal and the frequency of oscillation of the input of second antenna;

Be used for producing certain frequency of oscillation and the frequency of oscillation that produces being outputed to the 3rd local oscillator of three-mixer according to control voltage from outside input; And

Be used for control voltage is outputed to the 3rd PLL of the 3rd local oscillator.

5, combination tuner according to claim 1, wherein the satellite frequency output is exported the signal with 479.5MHz frequency.

6, combination tuner according to claim 1, wherein first low pass filter is only by 860MHz in the RF signal or be lower than the RF signal composition of 860MHz.

7, combination tuner according to claim 1, wherein first switching device has first fixed terminals that is formed in first antenna output end, be formed in second fixed terminals of satellite frequency output output, and be connected to working end on the AGC according to the control signal of outside.

8, combination tuner according to claim 1, wherein the second switch device has the working end that is formed in second mixer output, be formed in first fixed terminals on second low pass filter, and being connected to second fixed terminals of the 3rd low pass filter, the second switch device is changed optionally the 2nd IF signal from the output of second frequency mixer is provided to second low pass filter or the 3rd low pass filter according to the control signal of outside.

9, combination tuner according to claim 1, wherein first switching device and second switch device are to be converted according to the QAM of system or the control of QPSK.

10, a kind of combination tuner that is used for ground and satellite broadcasting comprises:

Be used to receive the satellite frequency output of satellite electric wave and output certain frequency signal;

By external control signal optionally from the 2nd IF signal of second frequency mixer input or from first switching device of the RF signal output of satellite frequency output output;

Combine with first switching device work and the 2nd IF signal from first switching device output optionally is provided of second switch device;

The 3rd low pass filter only is used for by corresponding to the frequency from the satellite electric wave wave band of the 2nd IF of second switch device output.

11, combination tuner as claimed in claim 10, wherein second low pass filter is by 10MHz or be lower than the signal of 10MHz bandwidth.

12, combination tuner as claimed in claim 10, wherein the 3rd low pass filter is by 45MHz or be lower than the signal of 45MHz bandwidth.

13, combination tuner as claimed in claim 10, wherein the satellite frequency output comprises:

Be used to receive second antenna of satellite electric wave;

Be used for RF signal and frequency of oscillation from the input of second antenna are synthesized to export the three-mixer of certain frequency;

Be used for producing the 3rd local oscillator that certain frequency of oscillation also outputs to the frequency of oscillation that produces three-mixer according to external control voltage; And

14, combination tuner as claimed in claim 10, the wherein intermediate-freuqncy signal of satellite frequency output output 45MHz.

15, combination tuner as claimed in claim 10, wherein first low pass filter is only by having 860MHz or being lower than the RF signal composition of 860MHz frequency in the RF signal.

16, combination tuner as claimed in claim 10, wherein first switching device has first fixed terminals that is formed in second mixer output, be formed in second fixed terminals of satellite frequency output output, and be formed in the working end of second switch device output.

17, combination tuner as claimed in claim 10, wherein the second switch device has the working end that is formed in the first switching device place, be formed in first fixed terminals at the second low pass filter place, and being formed in second fixed terminals at the 3rd low pass filter place, the second switch device is changed with optionally being provided to second low pass filter or the 3rd low pass filter from the 2nd IF signal of second frequency mixer output or from the IF signal of satellite frequency output output according to external control signal.

18, combination tuner as claimed in claim 10, wherein first switching device and second switch device are to be converted according to the QAM of system or the control of QPSK.

19, a kind of combination tuner that is used for ground and satellite broadcasting comprises:

The double conversion tuner, it comprises first antenna, first amplifier, first low pass filter, first frequency mixer, first local oscillator, a PLL, band pass filter, second amplifier, second frequency mixer, second local oscillator and the 2nd PLL is characterized in that, also comprise:

Ground is output frequently, and it mainly comprises the ground wave antenna that is used to receive earthwave;

The satellite frequency output, it mainly comprises the certain frequency signal that the satellite electric wave antenna that is used to receive the satellite electric wave and output mix the frequency of oscillation and the satellite-signal of satellite electric wave antenna reception mutually;

First switching device is used for optionally providing the frequency from earthwave output or the output of satellite frequency output; And

Be formed in the second switch device of the first switching device rear end, be used for optionally will be being provided to the low pass filter that is suitable for earthwave and satellite electric wave through the signal of first switching device;