CN104284058A - Filtering system, filtering method, television signal receiver and receiving method - Google Patents

Abstract

The invention provides a filtering system, which comprises a first filtering module, wherein the first filtering module comprises a first frequency converter and a first filter. The first frequency converter comprises a central frequency control end for receiving a first control signal and an input end for receiving an input signal, and executes a first frequency conversion action on the input signal by taking a first control frequency of the first control signal as a central frequency. The first filter performs a first filtering operation on the input signal according to an equivalent impedance of a circuit coupled to the input terminal to cooperate with the first frequency converter to generate a first filtered input signal at an output terminal of the filtering system, wherein the equivalent impedance determines a bandwidth of the first filtered input signal.

Description

Filtering system, filtering method, TV signal receiver and receiving method

technical field

The present invention relates to a filtering system, a filtering method, a television signal receiver and a television signal receiving method, in particular to a filtering system, a filtering method, a television signal receiver and a television signal receiving method for filtering signals with a frequency conversion action.

Background technique

The TV system will perform down-conversion for one or more channels to obtain TV data, but if the overall bandwidth of the system is too large and there are too many channels, it may happen that even channels with harmonic frequencies are down-converted together . For example, when down-converting a 100MHZ channel, the channels with its odd harmonic frequencies (eg, 300MHz, 500MHz) are down-converted together, so the signals of these channels will be added together, affecting all channels. The data accuracy of the desired channel.

In addition, the frequency range covered by the TV video signal is quite wide, for example, from 40MHz to 1000MHz, so it also covers quite a lot of channels. Because the signal strength of each channel is different, in order to be able to correspond to all channels, the front-end circuit must have a relatively high dynamic range, which will reduce the linearity of the front-end circuit. In addition, some TV systems connect multiple tuners together in a loop in order to obtain multi-channel TV data. However, under such a structure, the signal will have more loss due to the loop, and the power consumption and cost will also increase accordingly.

Contents of the invention

Therefore, an object of the present invention is to provide a filtering system and a filtering method for filtering various signals with a simple filter structure.

Another object of the present invention is to provide a TV signal receiver and a TV signal receiving method for filtering the TV signal with a simple filter structure to solve the above problems.

An embodiment of the present invention provides a filtering system, which includes a first filtering module, and the first filtering module includes a first frequency converter and a first filter. The first frequency converter includes a center frequency control terminal receiving a first control signal and an input terminal receiving an input signal, and performs a first control operation on the input signal with a first control frequency of the first control signal as the center frequency A frequency conversion action. The first filter performs a filtering action on the input signal according to the equivalent impedance of the circuit coupled to the input end, so as to cooperate with the first frequency converter to generate a first filtered input signal at an output end of the filtering system , wherein the equivalent impedance determines the frequency bandwidth of the first filtered input signal.

An embodiment of the present invention provides a TV signal receiver, which includes a filter system with a first filter module, an analog-to-digital converter, and a digital front-end processor. The first filter module includes: a first frequency converter, including a center frequency control terminal receiving a first control signal, and an input terminal receiving a TV signal, and using a first control frequency of the first control signal as The center frequency performs a first frequency conversion operation on the TV signal; and a first filter performs a first filter operation on the TV signal according to the equivalent impedance of the circuit coupled to the input terminal to match the first frequency conversion A filter generates a first filtered television signal at an output end of the filter system, wherein the equivalent impedance determines the frequency bandwidth of the first filtered television signal. The analog-to-digital converter performs a digitization operation according to the first filtered TV signal to generate a digital filtered TV signal. A digital front-end processor is used for processing the digital filtered TV signal.

According to the aforementioned embodiments, a simple filter combination can be used to filter the signal, and by filtering the TV signal before it enters the A/D processor, the burden on the A/D processor can be lightened.

Description of drawings

In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and understandable, the specific embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein:

FIG. 1A is a block diagram of a filtering module according to an embodiment of the invention.

FIG. 1B is a schematic diagram illustrating the operation of the filtering module shown in FIG. 1A .

FIG. 2A shows a block diagram of filter modules connected in series according to an embodiment of the present invention.

FIG. 2B is a schematic diagram illustrating the operation of the circuit shown in FIG. 2A .

FIG. 3A shows a block diagram of parallel connection of filter modules according to an embodiment of the present invention.

FIG. 3B is a schematic diagram illustrating the operation of the circuit shown in FIG. 3A .

FIG. 4 illustrates a detailed circuit diagram of a filtering module according to an embodiment of the present invention.

FIG. 5 is a schematic diagram of the circuit structure shown in FIG. 4 applied to the circuit shown in FIG. 2A .

FIG. 6 is a schematic diagram of the circuit structure shown in FIG. 4 applied to the circuit shown in FIG. 3A .

FIG. 7 is a schematic diagram of using the structure of FIG. 2A in a television signal receiver.

FIG. 8 is a schematic diagram of the structure of FIG. 3A used in a television signal receiver.

FIG. 9 is a flowchart of a filtering method according to an embodiment of the present invention.

FIG. 10 is a flow chart of a TV signal receiving method according to an embodiment of the invention.

Explanation of symbols in the figure:

G ₁ , G ₂ , G ₃ filter modules

FRF ₁ , FRF ₂ , FRF ₃ inverters

LF ₁ , LF ₂ , LF ₃ low-pass filters

CST ₁ center frequency control terminal

INT input

Out, Out ₁ , Out ₂ , Out ₃ output terminals

Buf ₁ , Buf ₂ , Buf ₃ buffers

C variable capacitor

L variable inductance

Tr ₁ first switching element

Tr ₂ second switching element

Tr ₃ third switching element

Tr ₄ fourth switching element

First end of T _F1 , T ₁₁ , T ₂₁ , T ₃₁ , T ₄₁

T _F2 , T ₁₂ , T ₂₂ , T ₃₂ , T ₄₂ second end

T _1C , T _2C , T _3C , T _4C control terminals

700, 800 TV signal receiver

701, 801 Receiver circuit

703, 803 Analog to Digital Converter

705, 805 digital front-end processor

707, 807 phase lock loop

709, 809 filter system

711, 811 Mixer

813 multiplexer

815 adder

LNA _R RF end amplifier

LNA, LNA _I , LNA ₂ , LNA ₃ IF amplifier

Detailed ways

FIG. 1A shows a block diagram of a filtering module G ₁ according to an embodiment of the present invention. As shown in FIG. 1A , the filtering module G ₁ includes a frequency converter FRF ₁ and a low-pass filter LF ₁ . The frequency converter FRF ₁ includes a center frequency control terminal CST ₁ receiving a control signal CS ₁ , and an input terminal INT receiving an input signal IN. And take a control frequency _CF1 of the control signal _CS1 as the center frequency to perform a frequency conversion operation on the input signal IN. The low-pass filter LF ₁ performs a low-pass filtering action on _the input signal IN according to the equivalent impedance Z _L of the circuit coupled to _the input terminal INT, so as to cooperate with the frequency converter FRF ₁ to generate A filtered input signal FIN ₁ . Note however that the low-pass filter LF ₁ can be replaced by other types of filters such as high-pass filters. The filtered input signal FIN ₁ may come from either the frequency converter FRF ₁ or the low-pass filter LF ₁ depending on the structure of the frequency converter FRF ₁ and the low-pass filter LF ₁ . Please note that if the filter module G ₁ is a single-port device, the input terminal INT and the output terminal Out ₁ can be the same terminal.

FIG. 1B is a schematic diagram illustrating the operation of the filtering module shown in FIG. 1A . As shown in FIG. 1B , the frequency converter FRF ₁ converts the frequency of the input signal IN with the control frequency CF ₁ as the center frequency. Moreover, the low-pass filter _LF1 performs a low-pass filtering action on the input signal IN according to the equivalent impedance Z _L of the circuit coupled to the input terminal INT, so that part of the signal is filtered out, such as the oblique part in FIG. 1B . When the value of the equivalent impedance Z _L is different, the part of the signal to be filtered is also different. Taking FIG. 1B as an example, the value of Z _Lb is greater than the value of Z _La . Therefore, the low-pass filtering operation performed by Z _La will remove more signal parts than the low-pass filtering operation performed by Z _Lb. In other words, the value of the equivalent impedance Z _L determines the frequency bandwidth of the filtered input signal FIN ₁ . Please note that the above-mentioned frequency conversion action and filtering action are not in sequence, and may be executed at the same time. In short, as long as a filtering module performs frequency conversion and low-pass filtering on the input signal to obtain the filtered signal as shown in FIG. 1B , it is within the scope of the present invention.

FIG. 2A shows a block diagram of filter modules connected in series according to an embodiment of the present invention. As shown in FIG. 2A , the filtering system 200 further includes filtering modules G ₂ and _{G 3 in} addition to the filtering module G 1 shown in FIG. 1 . The filtering modules G ₂ and G ₃ respectively include frequency converters FRF ₂ and FRF ₃ and low-pass filters LF ₂ and LF ₃ . The filtering modules G ₁ G ₂ and G ₃ operate simultaneously to generate the filtered input signal FIN, which is output at the output terminal Out of the filtering system 200 . However, please note that although three sets of filter modules are used for illustration in FIG. 2A , it is not limited to three sets, and other sets can also be used. In one embodiment, the filter system 200 is a single-port device, so the filter modules G ₁ G ₂ and G ₃ operate simultaneously to generate the filtered input signal FIN, but the filter system 200 is not limited to be a single-port device. As long as the filtering system is connected in series and can operate simultaneously, it should be within the scope of the present invention.

FIG. 2B is a schematic diagram illustrating the operation of the circuit shown in FIG. 2A . As shown in FIG. 2B , the original input signal IN contains a lot of unnecessary information besides the required TV data. After being jointly processed by the filtering modules G ₁ G ₂ and G ₃ , the filtered input signal FIN will retain the desired channel signal. That is, the signals of the channels whose center frequencies are CF ₁ , CF ₂ and CF ₃ (the frequencies of the control signals CS ₁ , CS ₂ and CS ₃ ). In addition, the equivalent impedance Z _L also determines which parts of the signal will be filtered out (the oblique lines in FIG. 2B ).

FIG. 3A shows a block diagram of parallel connection of filter modules according to an embodiment of the present invention. As shown in FIG. 3A , the filtering system 300 further includes filtering modules G ₂ and _{G 3 in} addition to the filtering module G 1 shown in FIG. 1 . Different from FIG. 2A, each group of filtering modules in FIG. 3A is independent. Therefore, the signal input to each frequency converter is the input signal IN, but different frequency converters FRF ₁ , FRF ₂ and FRF ₃ use different control signals CS ₁ , CS ₂ and CS ₃ to perform frequency conversion operations. With such a structure, the filtering modules G ₁ , G ₂ , and G ₃ will respectively output corresponding filtered input signals FIN ₁ , FIN ₂ , and FIN ₃ . In one embodiment, the filtering system 300 further includes buffers Buf ₁ , Buf ₂ and Buf ₃ respectively located on the output ports Out ₁ , Out ₂ and Out ₃ of the filtering modules G ₁ , G ₂ and G ₃ . With the buffers Buf ₁ , Buf ₂ and Buf ₃ , each filter module can be separated so that the impedances thereof will not interfere with each other. However, please note that although three sets of frequency converters and low-pass filters are used for illustration in FIG. 3A , they are not limited to three sets, and other sets may also be used.

FIG. 3B is a schematic diagram illustrating the operation of the circuit shown in FIG. 3A . As shown in Figure 3B, the input signal IN has the signals of each channel and other noises, and after being processed by the circuit shown in Figure 3A, it will be at the output terminals Out ₁ and Out of the filter modules G ₁ , G ₂ , and G _{3 2} and Out ₃ respectively generate filtered input signals FIN ₁ , FIN ₂ , and FIN ₃ . How to generate the filtered input signals FIN ₁ , FIN ₂ , and FIN ₃ and their signal content has been described in detail before, so it will not be repeated here.

FIG. 4 shows a detailed circuit diagram of a filtering module according to an embodiment of the present invention. Please refer to FIG. 1 and FIG. 4 together for a better understanding of the content of the present invention. As shown in FIG. 4 , the low-pass filter LF ₁ includes a variable resistor R and a variable capacitor C (but not limited thereto), as well as a first terminal TF ₁ and a second terminal TF ₂ . The frequency converter FRF ₁ includes a first switch element Tr ₁ , a second switch element Tr ₂ , a third switch element Tr ₃ and a fourth switch element Tr ₄ . The first switching element Tr ₁ includes a first terminal T ₁₁ coupled to the first terminal T _F1 of the low-pass filter LF ₁ , a switch control terminal T _1C coupled to the center frequency control terminal CST ₁ , and coupled to the input A second terminal T ₁₂ of the terminal INT. The second switching element Tr ₂ includes a first terminal T ₂₁ coupled to a second terminal T _F2 of the low-pass filter LF ₁ , a switch control terminal T _2C coupled to the center frequency control terminal CST ₁ , and coupled to the A second terminal T ₂₂ of the input terminal INT. The third switching element Tr ₃ includes a first terminal T ₃₁ coupled to the first terminal T _F1 of the low-pass filter LF ₁ , a switch control terminal T _3C coupled to the center frequency control terminal CST ₁ , and coupled to the output terminal A second terminal T ₃₂ of Out ₁ . The fourth switching element Tr ₄ includes a first terminal T ₄₁ coupled to a second terminal T _F2 of the low-pass filter LF ₁ , a switch control terminal T _4C coupled to the center frequency control terminal CST ₁ , and coupled to the A second terminal T ₄₂ of the output terminal Out ₁ .

FIG. 5 is a schematic diagram of the circuit structure shown in FIG. 4 applied to the circuit shown in FIG. 2A . As shown in FIG. 5 , after the input signal IN is input into the communication module G ₁ , the filtered input signal FIN is formed through common processing of the communication modules G ₁ , G ₂ and G ₃ . The detailed structure and operation mode of FIG. 5 have been described in FIG. 2A and FIG. 4 in detail, so they will not be repeated here.

FIG. 6 is a schematic diagram of the circuit structure shown in FIG. 4 applied to the circuit shown in FIG. 3A . As shown in Figure 6, after the input signal IN is respectively input into the communication modules G ₁ , G ₂ and G ₃ , the filtered input signals FIN ₁ , FIN ₂ and FIN are sequentially processed by the communication modules G ₁ , G ₂ and G _{3 3} and output at the output terminals Out ₁ , Out ₂ and Out ₃ respectively. The detailed structure and operation of FIG. 6 have been described in FIG. 3A and FIG. 4 , so details are not repeated here.

FIG. 7 shows a schematic diagram of using the structure of FIG. 2A in a television signal receiver 700 . As shown in FIG. 7 , the television signal receiver 700 includes a receiver circuit 701 , an analog-to-digital converter 703 , a digital front-end processor 705 and a phase-locked loop 707 . The input signal IN is a TV signal. The filtering system 709 according to the embodiment of the present invention is located in the receiving end circuit 701 . The receiver circuit 701 includes a radio frequency amplifier LNA _R , a mixer 711 and an intermediate frequency amplifier LNA _I . The mixer 711 is used to receive the local oscillation signal LO from the phase-locked loop 707 (which can also be regarded as a local oscillator), so as to carry the received input signal IN from the radio frequency to the intermediate frequency, and then process it through the filter system 709 with a series structure After that, the filtered input signal FIN is output. The filtered input signal FIN is amplified by the intermediate frequency amplifier LNA _I and then processed by the analog-to-digital converter 703 , and the digitized signal is output to the digital front-end processor 705 . In one embodiment, the control signal CS received by the filter system 709 is the local oscillator signal LO. However, please note that the TV signal receiver 700 may not include the mixer 711 , so that the input signal IN will not be carried to the intermediate frequency, but will be amplified by the RF amplifier LNA _R before entering the filtering system 700 .

FIG. 8 is a schematic diagram of the structure of FIG. 3A used in a television signal receiver. The structure of FIG. 8 is similar to that of FIG. 7 , and the TV signal receiver 800 includes a receiver circuit 801 , an analog-to-digital converter 803 , a digital front-end processor 805 and a phase-locked loop 807 . And the filtering system 809 according to the embodiment of the present invention is located in the receiving end circuit 801 . The difference between FIG. 7 and FIG. 8 is that the filter modules in the communication system 809 are connected in parallel, and are located after the intermediate frequency amplifiers LNA _I1 , LNA _I2 and LNA _I3 . The mixer 811 is used to receive the local oscillation signal LO from the phase-locked loop 807 (which can also be regarded as a local oscillator), so as to carry the received input signal IN from the radio frequency to the intermediate frequency, and then process it through the filter system 809 with parallel structure Afterwards, the filtered input signals FIN ₁ , FIN ₂ and FIN ₃ are respectively output. The filtered input signals FIN ₁ , FIN ₂ and FIN ₃ are summed by the adder 815 to generate a summed and filtered TV signal which is processed by the analog-to-digital converter 803 and the digitized signal is output to the digital front-end processor 805 . In the embodiments of FIG. 7 and FIG. 8 , the burden of the analog-to-digital converters 703 and 803 can be reduced by performing preliminary filtering before entering the analog-to-digital converters. In this way, too precise analog-to-digital converter is not needed, which can reduce the cost of the circuit. However, please note that the TV signal receiver 800 may not include the mixer 811 , so that the input signal IN will not be carried to the intermediate frequency, but will be amplified by the radio frequency amplifier LNA _R before entering the filter system 700 .

The aforementioned components and their arrangement in FIG. 7 and FIG. 8 are for example only, and are not intended to limit the present invention. For example, the filtering systems in Fig. 7 and Fig. 8 are all after the radio frequency end amplifier LNA _R , the intermediate frequency end amplifiers LNA _I1 , LNA I2 and _{LNA I3 and} the mixers 711, 811, but the filtering system can also be located at the radio frequency end After the amplifier LNA _R , the intermediate frequency amplifiers LNA _I1 , LNA _I2 and LNA _I3 and the mixers 711 and 811 . In addition, the filter system can also be located after the RF-side amplifier LNA _R , the IF-side amplifiers LNA _I1 , LNA _I2 and LNA _I3 but before the mixer.

FIG. 9 shows a flowchart of a filtering method according to an embodiment of the present invention, which includes the following steps:

Step 901

An input signal (for example, the input signal IN in FIG. 1A ) is received at an input end of a filter system.

Step 903

A first frequency conversion operation is performed on the input signal with a first control frequency of a first control signal (eg, CS ₁ in FIG. 1A ) as the center frequency.

Step 905

Perform a filtering action on the input signal according to the equivalent impedance of the circuit coupled to the input end, so as to cooperate with the first frequency conversion action to generate a first filtered input signal at an output end of the filtering system, wherein the equivalent The impedance determines the bandwidth of the first filtered input signal (eg, FIN ₁ in FIG. 1B ).

Fig. 10 depicts a flow chart of a television signal receiving method according to an embodiment of the present invention, which corresponds to Fig. 7 and Fig. 8 and includes the following steps:

Step 1001

A television signal (for example, input signal IN in FIGS. 7 and 8 ) is received at an input of the filter system.

Step 1003

A first frequency conversion operation is performed on the TV signal with a first control frequency of a first control signal (for example, the control signal CS ₁ in FIG. 7 and FIG. 8 ) as the center frequency. Step 1005

Perform a filtering action on the TV signal according to the equivalent impedance of the circuit coupled to the input end, so as to cooperate with the first frequency conversion action to generate a first filtered TV signal at an output end of the filtering system, wherein the equivalent Impedance determines the bandwidth of the first filtered television signal.

Step 1007

A digitization operation is performed according to the first filtered TV signal to generate a digital filtered TV signal.

Step 1009

A digital front-end processor is used to process the digitally filtered television signal (for example, 705, 805 in FIG. 7 and FIG. 8).

According to the aforementioned embodiments, a simple filter combination can be used to filter the signal, and by filtering the TV signal before it enters the ADP, the burden on the ADP can be lightened.

Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make some modifications and improvements without departing from the spirit and scope of the present invention. Therefore, the present invention The scope of protection should be defined by the claims.

Claims (22)

1. A filter system, comprising: an output terminal; A first filter module, comprising: A first frequency converter includes a center frequency control terminal and an input terminal, the center frequency control terminal receives a first control signal, the input terminal receives an input signal and is coupled to a circuit, the circuit has an equivalent impedance, the The first frequency converter performs a first frequency conversion operation on the input signal with a first control frequency of the first control signal as the center frequency; and A first filter, which performs a first filtering action on the input signal according to the equivalent impedance, so as to cooperate with the first frequency converter to generate a first filtered input signal at the output end of the filtering system, wherein the The effective impedance determines the frequency bandwidth of the first filtered input signal. 2. The filter system according to claim 1, wherein the first filter is a high-pass filter or a low-pass filter. 3. The filter system according to claim 1, wherein the first frequency converter comprises: A first switch element, including a first terminal, a second terminal and a switch control terminal, the first terminal is coupled to a first terminal of the first filter, the switch control terminal is coupled to the center frequency control terminal , the second terminal is coupled to the input terminal; A second switch element, including a first terminal, a second terminal and a switch control terminal, the first terminal is coupled to a second terminal of the first filter, the switch control terminal is coupled to the center frequency control terminal , the second terminal is coupled to the input terminal; A third switch element, including a first terminal, a second terminal and a switch control terminal, the first terminal is coupled to a first terminal of the first filter, the switch control terminal is coupled to the center frequency control terminal , the second terminal is coupled to the output terminal; and A fourth switching element, including a first terminal, a second terminal and a switch control terminal, the first terminal is coupled to a second terminal of the first filter, the switch control terminal is coupled to the center frequency control terminal , the second end is coupled to the output end. 4. The filtering system of claim 1, further comprising: A second filter module, comprising: A second frequency converter, including a center frequency control terminal and an input terminal, the center frequency control terminal receives a second control signal, the input terminal receives the first filtered input signal and is coupled to a circuit, the circuit has etc. effective impedance, the second frequency converter takes a second control frequency of the second control signal as the center frequency and performs the first frequency conversion action on the input signal together with the first frequency converter; and A second filter, performing the first filtering action on the input signal together with the first filter according to the equivalent impedance, so as to cooperate with the first frequency converter, the second frequency converter and the first filter in the the output terminal of the filtering system generates a second filtered input signal as the first filtered input signal; Wherein the first frequency converter, the second frequency converter, the first filter and the second filter operate simultaneously to generate the second filtered input signal. 5. The filtering system of claim 1, further comprising: A second filter module, comprising: A second frequency converter, including a center frequency control terminal and an input terminal, the center frequency control terminal receives a second control signal, the input terminal receives the input signal and is coupled to a circuit, the circuit has an equivalent impedance, and performing a second frequency conversion operation on the input signal with a second control frequency of the second control signal as the center frequency; and A second filter performs a second filtering action on the input signal according to the equivalent impedance, so as to cooperate with the second frequency converter to generate a second filtered input signal at the output end of the filtering system. 6. The filtering system of claim 5, further comprising: a first buffer coupled to the output end of the first filtering module; and A second buffer is coupled to the output end of the second filtering module. 7. A TV signal receiver, comprising: A filter system, comprising: an output terminal; and A first filter module, comprising: A first frequency converter includes a center frequency control terminal and an input terminal, the center frequency control terminal receives a first control signal, the input terminal receives a TV signal and is coupled to a circuit, the circuit has an equivalent impedance, the The first frequency converter performs a first frequency conversion operation on the television signal with a first control frequency of the first control signal as the center frequency; and A first filter, which performs a first filtering action on the TV signal according to the equivalent impedance, so as to cooperate with the first frequency converter to generate a first filtered TV signal at the output end of the filtering system, wherein the equivalent impedance determines the frequency bandwidth of the first filtered television signal; an analog-to-digital converter for performing a digitization operation on the first filtered television signal to generate a digital filtered television signal; and A digital front-end processor is used for processing the digital filtered TV signal. 8. The television signal receiver as claimed in claim 7, wherein the television signal is an intermediate frequency signal, and the television signal receiver further comprises: a phase locked loop circuit for providing the control signal; and A mixer converts a radio frequency television signal into the television signal according to the control signal. 9. The television signal receiver as claimed in claim 7, further comprising: a mixer for converting a radio frequency television signal into the television signal based on a local oscillator signal; a radio frequency amplifier for amplifying the radio frequency television signal and outputting the amplified radio frequency television signal to the mixer; a phase-locked loop circuit for providing the local oscillator signal; A second filter module, comprising: A second frequency converter, including a center frequency control terminal and an input terminal, the center frequency control terminal receives a second control signal, the input terminal receives the first filtered TV signal and is coupled to a circuit, the circuit has etc. Effective impedance, the second frequency converter takes a second control frequency of the second control signal as the center frequency and performs the first frequency conversion action on the TV signal together with the first frequency converter; and A second filter, performing the first filtering action on the TV signal together with the first filter, so as to cooperate with the first frequency converter, the second frequency converter and the first filter in the filtering system The output produces a second filtered television signal as the first filtered television signal, wherein the first frequency converter, the second frequency converter, the first filter and the second filter operate simultaneously, wherein The equivalent impedance determines the frequency bandwidth of the second filtered television signal, and the analog-to-digital converter generates the digitally filtered television signal based on the second filtered television signal; and An intermediate frequency amplifier is located between the second filtering module and the analog-to-digital converter. 10. The television signal receiver as claimed in claim 7, further comprising: a mixer for converting a radio frequency television signal into the television signal based on a local oscillator signal; a radio frequency amplifier for amplifying the radio frequency television signal and outputting the amplified radio frequency television signal to the mixer; a phase-locked loop circuit for providing the local oscillator signal; A second filter module, comprising: A second frequency converter, including a center frequency control terminal and an input terminal, the center frequency control terminal receives a second control signal, the input terminal receives the TV signal and is coupled to a circuit, the circuit has an equivalent impedance, and performing a second frequency conversion operation on the television signal with a second control frequency of the second control signal as the center frequency; and A second filter, which performs a second filtering action on the TV signal according to the equivalent impedance, so as to cooperate with the second frequency converter to generate a second filtered TV signal at an output end of the second filtering module, wherein the The equivalent impedance determines the frequency bandwidth of the second filtered television signal; an adder for generating a summed filtered television signal from the first filtered television signal and the second filtered television signal, wherein the analog-to-digital converter generates the digital filtered television signal from the summed filtered television signal ;as well as At least one intermediate frequency amplifier is located in front of the second filtering module and the first filtering module. 11. The television signal receiver as claimed in claim 10, further comprising: a first buffer coupled to the output end of the first filtering module; and A second buffer is coupled to the output end of the second filtering module. 12. The television signal receiver as claimed in claim 7, wherein the filter is a high-pass filter or a low-pass filter. 13. The television signal receiver as claimed in claim 7, wherein the first frequency converter comprises: A first switch element, including a first terminal, a second terminal and a switch control terminal, the first terminal is coupled to a first terminal of the first filter, the switch control terminal is coupled to the center frequency control terminal , the second terminal is coupled to the input terminal; A second switch element, including a first terminal, a second terminal and a switch control terminal, the first terminal is coupled to a second terminal of the first filter, the switch control terminal is coupled to the center frequency control terminal , the second terminal is coupled to the input terminal; A third switch element, including a first terminal, a second terminal and a switch control terminal, the first terminal is coupled to a first terminal of the first filter, the switch control terminal is coupled to the center frequency control terminal , the second terminal is coupled to the output terminal; and A fourth switching element, including a first terminal, a second terminal and a switch control terminal, the first terminal is coupled to a second terminal of the first filter, the switch control terminal is coupled to the center frequency control terminal , the second end is coupled to the output end. 14. A filtering method, used on a filtering system, the filtering system includes an input terminal and an output terminal, the input terminal is coupled to a circuit and the circuit has an equivalent impedance, the filtering method comprises: receiving an input signal through the input terminal; using a first frequency converter to perform a first frequency conversion action on the input signal with a first control frequency of a first control signal as the center frequency; and Using a first filter to perform a first filtering action on the input signal according to the equivalent impedance, so as to cooperate with the first frequency conversion action to generate a first filtered input signal at the output terminal, wherein the equivalent impedance determines the The frequency bandwidth of the first filtered input signal. 15. The filtering method according to claim 14, wherein the filtering action is a high-pass filtering action or a low-pass filtering action. 16. The filtering method according to claim 14, further comprising: using a second frequency converter with a second control frequency of a second control signal as the center frequency to perform the first frequency conversion action on the input signal together with the first frequency converter; and Using a second filter to perform the first filtering action on the input signal together with the first filter according to the equivalent impedance, so as to cooperate with the first frequency converter, the second frequency converter and the first filter in the the output terminal of the filtering system generates a second filtered input signal as the first filtered input signal; Wherein the first frequency converter, the second frequency converter, the first filter and the second filter operate simultaneously. 17. The filtering method according to claim 14, further comprising: using a second frequency converter to perform a second frequency conversion action on the input signal with a second control frequency of a second control signal as the center frequency; and A second filter is used to perform a second filtering action on the input signal according to the equivalent impedance, so as to cooperate with a second frequency conversion action to generate a second filtered input signal at the output end of the filtering system. 18. A television signal receiving method, used on a television signal receiving device comprising a filtering system, the filtering system comprising an input terminal and an output terminal, the input terminal is coupled to a circuit and the circuit has an equivalent impedance, the Television signal receiving methods include: receiving a television signal through the input terminal; Using a first control frequency of a first control signal as the center frequency to perform a first frequency conversion operation on the television signal; A filtering operation is performed on the television signal according to the equivalent impedance to produce a first filtered television signal at an output end of the filtering system in conjunction with the first frequency conversion operation, wherein the equivalent impedance determines the first filtered television signal the frequency bandwidth of television signals; performing a digitization operation on the first filtered television signal to generate a digitally filtered television signal; and The digitally filtered television signal is processed using a digital front-end processor. 19. The TV signal receiving method according to claim 18, wherein the TV signal is an intermediate frequency signal, and the TV signal receiver, the method further comprises: A radio frequency television signal is converted into the television signal according to the control signal. 20. The television signal receiving method as claimed in claim 18, wherein the filtering action is a high-pass filtering action or a low-pass filtering action. 21. The television signal receiving method as claimed in claim 18, further comprising: using a second frequency converter with a second control frequency of a second control signal as the center frequency to perform the first frequency conversion action on the television signal together with the first frequency converter; and Use a second filter to perform the first filtering action on the TV signal together with the first filter according to the equivalent impedance, so as to cooperate with the first frequency converter, the second frequency converter and the first filter in the the output of the filtering system produces a second filtered television signal as the first filtered television signal; Wherein the first frequency converter, the second frequency converter, the first filter and the second filter operate simultaneously. 22. The television signal receiving method as claimed in claim 18, further comprising: using a second frequency converter to perform a second frequency conversion action on the television signal with a second control frequency of a second control signal as the center frequency; and A second filter is used to perform a filtering action on the television signal according to the equivalent impedance, so as to cooperate with a second frequency conversion action to generate a second filtered television signal at the output end of the filtering system.