CN103841061B

CN103841061B - Receiving system and method for restraining adjacent channel interference

Info

Publication number: CN103841061B
Application number: CN201210487683.9A
Authority: CN
Inventors: 杨光
Original assignee: Beijing Zhongtian Technology Co Ltd
Current assignee: Beijing Zhongtian Technology Co Ltd
Priority date: 2012-11-26
Filing date: 2012-11-26
Publication date: 2017-01-25
Anticipated expiration: 2032-11-26
Also published as: CN103841061A

Abstract

The invention relates to a receiving system for restraining adjacent channel interference. The receiving system comprises a tuner, a demodulator and a controller. The demodulator comprises a signal processing unit, a forward error correction device and a control unit. After radio-frequency signals received by an antenna enter the tuner, the tuner down-converts a designated channel signal to a lower intermediate frequency and an intermediate frequency signal is output; the signal processing unit receives the intermediate frequency signal and carries out processing comprising demodulation on the intermediate frequency signal, and date to be corrected is output; the forward error correction device receives the date to be corrected and performs error correction processing on the date to be corrected, outputs a TS flow to the controller based on a standard format, and sends error code information to the control unit; the control unit sends intermediate frequency gain control to the tuner, sends a second control command to the signal processing unit, and forwards the error code information from the forward error correction device to the controller; and after receiving the TS flow and the error code information, the controller optimizes parameters for restraining the adjacent channel interference, and sends the optimized parameters to the tuner and the demodulator through the control command.

Description

Receiving system and method for inhibiting adjacent channel interference

Technical Field

The invention relates to the field of digital television receiving and demodulating, in particular to a receiving system and a method for inhibiting adjacent channel interference.

Background

In recent years, the television industry in China is rapidly developed, and digital televisions are gradually replacing analog televisions to become mainstream of viewing modes. However, replacing analog televisions with digital televisions is a long-term process, the geographical environment of China is complex, and the receiving mode of digital televisions is not necessarily suitable for all regions, so that the phenomenon that analog televisions and digital televisions coexist exists in a long time period. The analog television comprises a wireless mode and a wired mode, and the coexistence of the wireless analog television and the digital television causes great pressure on originally limited spectrum resources, so that the problem of Adjacent Channel Interference (ACI) generally exists.

The adjacent channel interference means: in the edge region of signal coverage, strong adjacent channel interference can cause difficulty in correctly demodulating the signal, thereby seriously affecting the coverage area of the signal. In order to reduce the interference of the adjacent channel signal, the entire demodulation system should have sufficient adjacent channel interference resistance. The prior art demodulation system includes a tuner and a demodulator, wherein an intermediate frequency filter in the tuner is the most important means for suppressing the adjacent channel signal, and the final demodulation result is given by the demodulator, so that the optimal adjacent channel interference resistance can be obtained only by combining the demodulator and the tuner.

Due to the large number of models of tuners, they may have different parameters that are sensitive to adjacent channel interference. This requires that the tuner have some self-adaptive and self-adjusting capabilities to cope with the requirements of different tuners for adjacent channel performance. However, in the prior art, the demodulator in the demodulation system does not have the capability of automatically adapting and adjusting according to the tuner. In addition, the demodulation system in the prior art can only configure the average performance of each module to be optimal, but the demodulation system formed by combining the modules together does not necessarily show the optimal anti-ACI performance.

Disclosure of Invention

The invention aims to overcome the defect that the prior demodulation system can not obtain the best anti-ACI performance, thereby providing a receiving system and a receiving method which can effectively inhibit adjacent channel interference.

In order to achieve the above object, the present invention provides a receiving system for suppressing adjacent channel interference, comprising a tuner (110), a demodulator (120) and a controller (130), wherein the demodulator (120) comprises a signal processing unit (121), a forward error corrector (122) and a control unit (123); wherein,

after the radio frequency signal (140) received by the antenna enters the tuner (110), the tuner (110) down-converts the appointed channel signal to a lower intermediate frequency according to a first control command (148) sent by the controller (130), and then outputs an intermediate frequency signal (141) according to the strength requirement of an intermediate frequency gain control (144) sent by a control unit (123) in the demodulator (120); the signal processing unit (121) receives the intermediate frequency signal (141) and performs processing including demodulation on the intermediate frequency signal under the control of a second control command (145) issued by the control unit (123), and then outputs data (142) to be corrected; the forward error corrector (122) receives data (142) to be corrected, performs error correction processing on the data, outputs TS (transport stream) 143 to the controller (130) according to a standard format after error correction, and simultaneously sends error code information (146) to the control unit (123); -said control unit (123) sends an intermediate frequency gain control (144) to said tuner (110) under control of a control command (148) issued by said controller (130), sends a second control command (145) to said signal processing unit (121), forwards error information (146) from said forward error corrector (122) to said controller (130); the controller (130) optimizes parameters for suppressing adjacent channel interference according to the error code information (147) after receiving the TS stream (143) and the error code information (147), and then transmits the optimized parameters to the tuner (110) and the demodulator (120) through the control command (148).

In the foregoing technical solution, the parameters for suppressing adjacent channel interference include: a lock frequency point value of the tuner (110), a gain value of a preceding low noise amplifier, a characteristic parameter value of an intermediate frequency filter, and a characteristic parameter value of a baseband filter of the demodulator (120).

The invention also provides a method for suppressing adjacent channel interference, which is realized on the receiving system for suppressing adjacent channel interference, and comprises the following steps:

step 1), locking the current frequency point of a tuner (110) to a frequency point F;

the frequency point F refers to a central frequency point of a frequency band where a program to be received is located;

step 2), the controller (130) configures the tuner (110) and the demodulator (120) by using default parameters, then the tuner (110) down-converts the signal of the F frequency point to a preset intermediate frequency, and outputs the obtained intermediate frequency signal to the demodulator (120), the demodulator (120) demodulates the intermediate frequency signal, and in addition, the signal strength of a locked channel and the strength of an adjacent frequency signal are also obtained;

step 3), according to the demodulation result of the intermediate frequency signal, the signal intensity of the locked channel and the intensity of the adjacent frequency signal obtained in the step 2), the controller (130) judges whether strong ACI exists or not and the error rate after demodulation is high, if so, step 4) is executed, otherwise, step 16) is executed;

step 4), the controller (130) judges whether parameter optimization is already carried out, if so, step 5) is executed, otherwise, step 7) is executed;

step 5), the controller (130) reads the stored optimization parameters, and configures the tuner (110) and the demodulator (120) according to the optimization parameters;

step 6), the controller (130) judges whether the error rate is high, if so, step 7) is executed, otherwise, step 16) is executed;

step 7), the controller (130) judges whether the operation of the tuner (110) for moving the locked frequency point is effective for inhibiting the ACI, if so, the step 8) is executed, otherwise, the step 9) is executed;

step 8), the controller (130) optimizes the frequency point to obtain the value of the frequency point with the best performance, and then the next step is executed;

step 9), the controller (130) judges whether the tuner (110) can be configured with a front stage gain and has an effective effect on inhibiting ACI, if so, the step 10) is executed, otherwise, the step 11) is executed;

step 10), the controller (130) performs gain optimization to obtain a front-stage gain control value with optimal performance, and then executes the next step;

step 11), the controller (130) judges whether the tuner (110) can configure the intermediate frequency filter and has effective effect on inhibiting ACI, if so, the step 12) is executed, otherwise, the step 13) is executed;

step 12), the controller (130) optimizes the intermediate frequency filter, returns the optimal performance parameters of the intermediate frequency filter, and then executes the next step;

step 13), the controller (130) judges whether the demodulator (120) is required to further inhibit ACI, if so, step 14) is executed, otherwise, step 15) is executed;

step 14), the controller (130) optimizes the baseband filter, returns the optimal performance parameters of the baseband filter, and then executes the next step;

step 15), the controller (130) saves the return parameters optimized in the previous step, and if the return parameters are not optimized, the default parameters are saved;

step 16), the controller (130) waits for a new command to enter or end the operation.

In the above technical solution, the step 8) includes:

step 8-1), the controller (130) initializes parameters, let F = Fo, let Fb = F, and then sets Fmax and Fs according to the tuner model; f is a current locking frequency point, Fo is a central frequency point of a channel where a signal is located, Fb is a performance optimal frequency point, Fs is the minimum frequency resolution of a tuner, and Fmax is the maximum frequency offset specified by an algorithm;

step 8-2), the controller (130) initializes parameters, let Ea = E, let Eb = Ea; wherein E is the error rate in the error code information, Ea and Eb both represent temporary local variables;

step 8-3), the controller (130) assigns values to the variables, and let Ea = E;

step 8-4), the controller (130) judges whether the value of Ea is less than half of the value of Eb, if yes, the next step is executed, otherwise, the step 8-6) is executed.

Step 8-5), the controller (130) updates the variables, let Eb = Ea, let Fb = F, and then executes the next step;

step 8-6), the controller (130) judges whether the absolute value of the difference between F and Fo is greater than or equal to Fmax, if so, the step 8-8) is executed, otherwise, the step 8-7) is executed;

step 8-7), the controller (130) updates the variables to make F = F + Fs, then sends a command to lock the tuner (110) at the F frequency point, and then re-executes step 8-3);

step 8-8), the controller (130) sends a command to enable the tuner to be locked at the Fb frequency point;

step 8-9), finishing frequency point optimization, and returning to the frequency point Fb with the best performance.

In the above technical solution, the step 10) includes:

step 10-1), the controller (130) initializes parameters including: initializing the parameter quantity N and an intermediate frequency gain parameter matrix A to be tested according to the model of the tuner (110), wherein N =0, and Ab = A [ N ]; wherein, the length of A is N, A0 is default parameter, Ab is best parameter, N is circulation variable;

step 10-2), the controller (130) initializes parameters including: let Ea = E, let Eb = Ea; wherein E is the error rate in the error code information, Ea and Eb both represent temporary local variables;

step 10-3), the controller (130) assigns values to the variables, and let Ea = E;

step 10-4), the controller (130) judges whether the value of Ea is less than half of the value of Eb, if yes, step 10-5) is executed, otherwise step 10-6) is executed;

step 10-5), the controller (130) updates the variables to let Eb = Ea and Ab = a [ n ], and then executes the next step;

step 10-6), the controller (130) judges whether N is less than N, if yes, step 10-7) is executed, otherwise step 10-8) is executed;

step 10-7), the controller (130) updates the variable, makes n = n +1, sends a command to make the tuner pre-gain control value a [ n ], and then re-executes step 10-3);

step 10-8), the controller (130) sends a command to make the front stage gain control value of the tuner (110) be Ab;

step 10-9), the gain optimization is finished, and the front stage gain control value Ab with the optimal performance is returned.

In the above technical solution, the step 12) includes:

step 12-1), the controller (130) initializes parameters including: initializing the parameter number N and a parameter matrix P of the intermediate frequency filter to be tested according to the model of the tuner (110), wherein N =0 and Pb = P [ N ]; wherein the length of P is N, P0 is default parameter, Pb is optimum parameter, N is circulation variable;

step 12-2), the controller (130) initializes parameters including: let Ea = E, let Eb = Ea, where E is the error rate in the error code information, and Ea and Eb both represent temporary local variables;

step 12-3), the controller (130) assigns values to the variables, and let Ea = E;

step 12-4), the controller (130) judges whether the value of Ea is less than half of the value of Eb, if yes, step 12-5) is executed, otherwise step 12-6) is executed;

step 12-5), the controller (130) updates the variables, let Eb = Ea, let Pb = P;

step 12-6), the controller (130) judges whether N < N, if yes, step 12-7) is executed, otherwise step 12-8) is executed;

step 12-7), the controller (130) updates the variables to n = n +1, then sends a command to configure the intermediate frequency filter in the tuner (110) to P [ n ], and then re-executes step 12-3);

step 12-8), the controller (130) sends a command to cause the configuration of the intermediate frequency filter in the tuner (110) to be Pb;

and 12-9) finishing the optimization of the intermediate frequency filter, and returning to the optimal performance parameter Pb of the intermediate frequency filter.

In the above technical solution, the step 14) includes:

step 14-1), the controller (130) initializes parameters including: initializing the parameter quantity N and a parameter matrix P of a baseband filter to be tested, wherein N =0, and Pb = P [ N ]; wherein the length of P is N, P0 is default parameter, Pb is optimum parameter, N is circulation variable;

step 14-2), the controller (130) initializes parameters including: let Ea = E, let Eb = Ea; wherein E is the error rate in the error code information, Ea and Eb both represent temporary local variables;

step 14-3), the controller (130) assigns values to the variables, and let Ea = E;

step 14-4), the controller (130) judges whether the value of Ea is less than half of the value of Eb, if yes, the next step is executed, otherwise, the step 14-6) is executed;

step 14-5), the controller (130) updates the variables, let Eb = Ea, let Pb = P;

step 14-6), the controller (130) judges whether N is less than N, if yes, the next step is executed, otherwise, the step 14-8 is executed;

step 14-7), the controller (130) updates the variable, let n = n +1, sends a command to cause the configuration of the baseband filter in the signal processing unit (121) to be P [ n ], and then re-executes step 14-3);

step 14-8), the controller (130) sends a command to configure the baseband frequency filter in the signal processing unit (121) to be the optimal performance parameter Pb;

step 14-9), finishing the optimization of the baseband filter, and returning to the optimal performance parameter Pb of the baseband filter.

The invention has the advantages that:

1. the system of the invention can exert the whole anti-ACI performance to the maximum extent, and the system can carry out self-adaptive updating aiming at different channel conditions, thereby having stronger field adaptability.

2. The present system does not have any limitation on the tuner, and thus can be applied to all tuners on the market. When the tuner can not contribute to the anti-ACI performance of the system, the system can still improve the anti-ACI performance through the demodulator, and the system has wide applicability.

Drawings

Fig. 1 is a schematic structural diagram of a receiving system for suppressing adjacent channel interference according to the present invention;

fig. 2 is a flow chart of a receiving method for suppressing adjacent channel interference according to the present invention;

fig. 3 is a flow chart of frequency point optimization in the receiving method for suppressing adjacent channel interference according to the present invention;

fig. 4 is a flowchart of gain optimization in the receiving method for suppressing adjacent channel interference according to the present invention;

fig. 5 is a flowchart of optimizing an intermediate frequency filter in the receiving method for suppressing adjacent channel interference according to the present invention;

fig. 6 is a flowchart of optimizing a baseband filter in the receiving method for suppressing adjacent channel interference according to the present invention.

Detailed Description

The invention will now be further described with reference to the accompanying drawings.

As shown in fig. 1, the receiving system for suppressing adjacent channel interference of the present invention includes a tuner 110, a demodulator 120, and a controller 130, wherein the demodulator 120 includes a signal processing unit 121, a forward error corrector 122, and a control unit 123; in the working process of the system, after a radio frequency signal 140 received by an external antenna enters a tuner 110, the tuner 110 down-converts a designated channel signal to a lower intermediate frequency according to a control command 148 sent by a controller 130, and then outputs an intermediate frequency signal 141 according to the strength requirement of an intermediate frequency gain control 144 sent by a control unit 123 in a demodulator 120; the signal processing unit 121 receives the intermediate frequency signal 141 and performs processing including demodulation thereon under the control of the control command 145 issued by the control unit 123, and then outputs the data to be error-corrected 142; the forward error corrector 122 receives the data 142 to be corrected, performs error correction processing on the data, outputs a TS stream 143 to the controller 130 according to a standard format, and sends error code information 146 to the control unit 123; the control unit 123 sends the intermediate frequency gain control 144 to the tuner 110, sends the control command 145 to the signal processing unit 121, and forwards the error code information 146 from the forward error corrector 122 to the controller 130 under the control of the control command 148 sent by the controller 130; the controller 130 optimizes the parameters for suppressing the adjacent channel interference according to the error code information 147 after receiving the TS stream 143 and the error code information 147, and then transmits the optimized parameters to the control unit 123 in the tuner 110 and the demodulator 120 through the control command 148.

The above is a description of the basic structure of the receiving system for suppressing adjacent channel interference of the present invention, and the receiving system mainly suppresses adjacent channel interference in two aspects during the working process, the first is realized by controlling the tuner through the demodulator, and the second is realized by the demodulator itself.

In a first aspect, controller 130 adjusts the parameters of tuner 110 via the bit error rate results returned by demodulator 120. The parameters that tuner 110 can adjust include: and locking a frequency point, a gain of a preceding-stage low noise amplifier and the characteristics of an intermediate frequency filter. The adjustment of the locked frequency point means that: and moving the locking frequency point to a direction far away from the adjacent frequency interference by taking the minimum frequency resolution of the used tuner as the stepping length. The adjustment of the gain of the front-stage low noise amplifier means that: the purpose of controlling the gain of the front stage is achieved by controlling the reference coefficient of a feedback loop of a front stage amplifying circuit of the tuner, so that the signal obtains the highest signal-to-noise ratio in the signal bandwidth range after passing through the front stage amplifier. Adjusting the if filter characteristic means: the roll-off and stop-band attenuation of the intermediate frequency filter in the tuner are adjusted, so that the adjacent frequency interference is suppressed to the maximum extent, and the energy output to the demodulator is reduced. The tuner with different models can be adjusted in one or more parameters, the parameter adjusting range can be selected according to a manual of the tuner, and when enough prior data exist, the parameter adjusting range can be reduced, and the algorithm efficiency can be improved. If the tuner used does not support adjustment of a parameter or if the parameter is not effective against adjacent channel interference, the parameter is not adjusted.

In a second aspect, the demodulator is conditioned. In some cases, no matter how the tuner parameters are adjusted, the demodulator still outputs more adjacent channel signals to the demodulator, and in this case, the demodulator can adjust the characteristics of a baseband signal filter thereof to further inhibit adjacent channel noise from entering a demodulation stage of the signals. In order to suppress the adjacent channel noise, it is necessary to increase the stop band attenuation of the baseband filter in the demodulator or increase the roll-off coefficient.

When ACI is determined to be present and causes a high demodulation error rate, the system will start suppressing ACI. The system first sets the feasibility of adjusting the parameters and the parameter ranges based on the model of the tuner 110. The system checks the error rate output by the forward error corrector 122 in the demodulator 120 through the controller 130 to determine whether the performance of suppressing the adjacent channel interference is improved. All the methods start to gradually adjust from the default parameters, and at the beginning, the default parameters are the optimal parameters, and the error rate output by the forward error corrector 122 under the default parameters is the optimal error rate. Adjusting the parameter to be the next value, and if the error rate output by the forward error corrector 122 is less than half of the optimal error rate, making the optimal error rate equal to the current error rate, and making the optimal parameter be the current parameter; otherwise nothing is done. And then, continuing to adjust the parameters and making the error rate judgment until all possible parameter values are tried. And finally, using the optimal parameter as the current parameter to obtain the optimal adjacent frequency noise suppression performance.

The steps related to the method of the present invention are described with reference to fig. 2 on the basis of the foregoing receiving system for suppressing adjacent channel interference.

Step 201), locking the current frequency point of the tuner 110 to the frequency point F. The frequency point F is a central frequency point of a frequency band where a program to be received is located.

Step 202), the controller 130 configures the tuner 110 and the demodulator 120 by using default parameters, then the tuner 110 down-converts the signal of the F frequency point to a preset intermediate frequency, and outputs the obtained intermediate frequency signal to the demodulator 120, and the demodulator 120 demodulates the intermediate frequency signal and further acquires the signal strength of the locked channel and the strength of the adjacent channel signal.

How to obtain the signal strength of the locked channel and the strength of the adjacent channel signal in this step is common knowledge of those skilled in the art, and therefore, will not be further described in this step.

Step 203), according to the demodulation result of the intermediate frequency signal, the signal strength of the locked channel and the strength of the adjacent frequency signal obtained in step 202), the controller 130 determines whether a strong ACI exists and the demodulated error rate is high, if yes, step 204) is executed, otherwise step 216) is executed.

In this step, it can be considered that a strong ACI exists when the signal strength of the adjacent channel is higher than the signal strength of the locked channel by a certain threshold, and the certain threshold is determined according to the type of the adjacent channel signal and the modulation mode of the desired signal, which is common knowledge of those skilled in the art and will not be further described in the present invention. The error rate of the demodulated intermediate frequency signal can be determined according to the modulation method and test experience of the signal.

Step 204), the controller 130 determines whether parameter optimization has been performed, if so, performs step 205), otherwise performs step 207).

Step 205), the controller 130 reads the stored optimization parameters and configures the tuner 110 and the demodulator 120 according to the optimization parameters.

Step 206), the controller 130 determines whether the bit error rate is high, if so, step 207) is executed, otherwise, step 216) is executed.

Step 207), the controller 130 determines whether the operation of the tuner 110 to move the locked frequency point is effective for suppressing ACI, if so, step 208) is executed, otherwise, step 209) is executed.

In this step, whether the operation of the tuner 110 for moving the locked frequency point is effective for suppressing ACI may be known in advance through a test method during system integration.

Step 208), the controller 130 performs frequency point optimization to obtain the value of the frequency point with the best performance, and then executes the next step.

Step 209), the controller 130 determines whether the tuner 110 can configure the pre-stage gain and it has a valid effect on suppressing ACI, if so, step 210) is performed, otherwise, step 211) is performed.

In this step, whether the tuner 110 can configure the pre-stage gain and the effective effect thereof on suppressing ACI can be known in advance by a test method at the time of system integration.

Step 210), the controller 130 performs gain optimization to obtain a pre-stage gain control value with optimal performance, and then executes the next step.

Step 211), the controller 130 determines whether the tuner 110 can configure the if filter and it has a valid effect on suppressing ACI, if so, performs step 212), otherwise performs step 213).

In this step, whether the tuner 110 can configure the if filter and its effective effect on suppressing ACI can be known in advance by a test method at the time of system integration.

Step 212), the controller 130 optimizes the if filter, returns the best performance parameters of the if filter, and then performs the next step.

Step 213), the controller 130 determines whether the demodulator 120 is required to further suppress ACI, if so, step 214) is performed, otherwise step 215) is performed.

In this step, whether the demodulator 120 is required to further suppress ACI can be known in advance by a test method at the time of system integration.

Step 214), the controller 130 optimizes the baseband filter, returns the best performance parameters of the baseband filter, and then performs the next step.

Step 215), the controller 130 saves the return parameters optimized in the previous step, and if not, saves the default parameters.

Step 216), the controller 130 waits for a new command input or an end operation.

The relevant steps in the above method are further described below.

Referring to fig. 3, the frequency point optimization involved in step 208) specifically includes the following steps:

step 302), the controller 130 initializes parameters, let F = Fo, let Fb = F, and then sets Fmax and Fs according to the tuner model. Wherein, F is the current locking frequency point, Fo is the central frequency point of the channel where the signal is located, Fb is the frequency point with the best performance, Fs is the minimum frequency resolution of the tuner (which can be set according to the tuner manual), and Fmax is the maximum frequency deviation designated by the algorithm (which can be adjusted according to the modulation mode of the actual transmitted signal).

Step 303), the controller 130 initializes the parameters let Ea = E and let Eb = Ea. Wherein E is the error rate in the error code information, Ea and Eb both represent temporary local variables.

Step 304), the controller 130 assigns a value to the variable, let Ea = E.

Step 305), the controller 130 judges whether the inequality Ea < (Eb/2) is satisfied, if so, step 306 is executed, otherwise, step 307) is executed.

Step 306), the controller 130 updates the variables let Eb = Ea and Fb = F, and then executes the next step.

Step 307), the controller 130 determines whether the inequality | F-Fo | ≧ Fmax is satisfied, if so, step 309 is performed), otherwise step 308) is performed.

Step 308), the controller 130 updates the variable to have F = F + Fs, and then sends a command to have the tuner 110 lock at the F frequency point, and then re-executes step 304).

Step 309), the controller 130 sends a command to lock the tuner at the Fb frequency point.

Step 310), finishing frequency point optimization, and returning to the frequency point Fb with the best performance.

With reference to fig. 4, the gain optimization involved in step 210) comprises in particular the following steps:

step 402), the controller 130 initializes parameters including: let N =0 and Ab = a [ N ] according to the number N of model initialization parameters of the tuner 110 and the intermediate frequency gain parameter matrix a to be tested. Where A is of length N, A0 is the default parameter, Ab is the best performance parameter, and N is the loop variable.

Step 403), the controller 130 initializes parameters including: let Ea = E, let Eb = Ea. Wherein E is the error rate in the error code information, and Ea and Eb both represent temporary local variables.

Step 404), the controller 130 assigns a value to the variable, let Ea = E.

Step 405), the controller 130 determines whether the inequality Ea < (Eb/2) is satisfied, if so, step 406 is executed, otherwise, step 407) is executed).

Step 406), the controller 130 updates the variables let Eb = Ea, let Ab = a [ n ], and then executes the next step.

Step 407), the controller 130 determines whether N < N, if so, performs step 408), otherwise performs step 409).

Step 408), the controller 130 updates the variable so that n = n +1, sends a command to make the tuner pre-stage gain control value a [ n ], and then re-executes step 404).

Step 409), controller 130 sends a command to set the front stage gain control value of tuner 110 to Ab.

Step 410), the gain optimization is finished, and the front stage gain control value Ab with the optimal performance is returned.

Referring to fig. 5, the optimization of the if filter implemented in step 212) specifically includes the following steps:

step 502), the controller 130 initializes parameters including: let N =0 and Pb = P [ N ] according to the number N of model initialization parameters of the tuner 110 and the intermediate frequency filter parameter matrix P to be tested. Where P is N in length, P0 is the default parameter, Pb is the best performance parameter, and N is the loop variable.

Step 503), the controller 130 initializes parameters including: let Ea = E and let Eb = Ea, where E is the error rate in the error information and Ea, Eb both represent temporary local variables.

Step 504), the controller 130 assigns a value to the variable, let Ea = E.

Step 505), the controller 130 judges whether inequality Ea < (Eb/2) is satisfied, if so, step 506 is executed, otherwise, step 507) is executed).

Step 506), the controller 130 updates the variables let Eb = Ea and let Pb = P.

Step 507), the controller 130 determines whether N < N, if so, performs step 508), otherwise performs step 509).

Step 508), the controller 130 updates the variable with n = n +1, then sends a command to configure the intermediate frequency filter in the tuner 110 to P [ n ], and then re-executes step 504).

Step 509), the controller 130 sends a command to configure the intermediate frequency filter in the tuner 110 to Pb.

Step 510), finishing the optimization of the intermediate frequency filter, and returning to the optimal performance parameter Pb of the intermediate frequency filter.

Referring to fig. 6, the optimizing the baseband filter in step 214) specifically includes the following steps:

step 602), the controller 130 initializes parameters including: initializing the parameter number N and the parameter matrix P of the baseband filter to be tested, and enabling N =0 and Pb = P [ N ]. Where P is N in length, P0 is the default parameter, Pb is the best performance parameter, and N is the loop variable.

Step 603), the controller 130 initializes parameters including: let Ea = E, let Eb = Ea. Wherein E is the error rate in the error code information, Ea and Eb both represent temporary local variables.

Step 604), the controller 130 assigns a value to the variable, let Ea = E.

Step 605), the controller 130 determines whether inequality Ea < (Eb/2) is satisfied, if so, step 606 is executed, otherwise, step 607) is executed.

Step 606), the controller 130 updates the variables let Eb = Ea and let Pb = P.

Step 607), the controller 130 determines if N < N, if yes, go to step 608), otherwise go to step 609).

Step 608), the controller 130 updates the variable to let n = n +1, sends a command to cause the configuration of the baseband filter in the signal processing unit 121 to be P [ n ], and then re-executes step 604).

Step 609), the controller 130 sends a command to configure the baseband frequency filter in the signal processing unit 121 to the optimal performance parameter Pb.

Step 610), finishing the optimization of the baseband filter, and returning to the optimal performance parameter Pb of the baseband filter.

Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and are not limited. Although the present invention has been described in detail with reference to the embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A receiving system for suppressing adjacent channel interference, comprising a tuner (110), a demodulator (120) and a controller (130), wherein the demodulator (120) comprises a signal processing unit (121), a forward error corrector (122) and a control unit (123); wherein,

after a radio frequency signal (140) received by an antenna enters the tuner (110), the tuner (110) down-converts a designated channel signal to a preset intermediate frequency according to a first control command (148) sent by the controller (130), and then outputs an intermediate frequency signal (141) according to the strength requirement of an intermediate frequency gain control (144) sent by a control unit (123) in the demodulator (120); the signal processing unit (121) receives the intermediate frequency signal (141) and performs processing including demodulation on the intermediate frequency signal under the control of a second control command (145) issued by the control unit (123), and then outputs data (142) to be corrected; the forward error corrector (122) receives data (142) to be corrected, performs error correction processing on the data, outputs TS (transport stream) 143 to the controller (130) according to a standard format after error correction, and simultaneously sends error code information (146) to the control unit (123); -said control unit (123) sends an intermediate frequency gain control (144) to said tuner (110) under control of a control command (148) issued by said controller (130), sends a second control command (145) to said signal processing unit (121), forwards error information (146) from said forward error corrector (122) to said controller (130); the controller (130) optimizes parameters for suppressing adjacent channel interference according to the error code information (147) after receiving the TS stream (143) and the error code information (147), and then transmits the optimized parameters to the tuner (110) and the demodulator (120) through the control command (148).

2. The receiving system for suppressing adjacent channel interference according to claim 1, wherein the parameters for suppressing adjacent channel interference include: a lock frequency point value of the tuner (110), a gain value of a preceding low noise amplifier, a characteristic parameter value of an intermediate frequency filter, and a characteristic parameter value of a baseband filter of the demodulator (120).

3. A method of suppressing adjacent channel interference, implemented on the adjacent channel interference suppressing receiving system of one of claims 1-2, comprising:

4. The method of claim 3, wherein said step 8) comprises:

step 8-1), the controller (130) initializes parameters, and makes F ═ Fo and Fb ═ F, and then sets Fmax and Fs according to the tuner model; f is a current locking frequency point, Fo is a central frequency point of a channel where a signal is located, Fb is a performance optimal frequency point, Fs is the minimum frequency resolution of a tuner, and Fmax is the maximum frequency offset specified by an algorithm;

step 8-2), the controller (130) initializes parameters, let Ea equal to E, let Eb equal to Ea; wherein E is the error rate in the error code information, Ea and Eb both represent temporary local variables;

step 8-3), the controller (130) assigns values to the variables, and let Ea be E;

step 8-4), the controller (130) judges whether the value of Ea is smaller than half of the value of Eb, if yes, the next step is executed, otherwise, the step 8-6) is executed;

step 8-5), the controller (130) updates the variable, enables Eb to be Ea and Fb to be F, and then executes the next step;

step 8-7), the controller (130) updates the variable, and makes F ═ F + Fs, then sends a command so that the tuner (110) is locked at the F frequency point, and then step 8-3) is executed again;

5. The method of claim 3, wherein said step 10) comprises:

step 10-1), the controller (130) initializes parameters including: initializing the parameter quantity N and an intermediate frequency gain parameter matrix A to be tested according to the model of the tuner (110), wherein N is 0, and Ab is A [ N ]; wherein, the length of A is N, A0 is default parameter, Ab is best parameter, N is circulation variable;

step 10-2), the controller (130) initializes parameters including: let Ea equal to E, let Eb equal to Ea; wherein E is the error rate in the error code information, Ea and Eb both represent temporary local variables;

step 10-3), the controller (130) assigns values to the variables, and let Ea be E;

step 10-5), the controller (130) updates the variables, enables Eb to be Ea and Ab to be A [ n ], and then executes the next step;

step 10-7), the controller (130) updates the variable, makes n equal to n +1, sends a command to make the front gain control value of the tuner be A [ n ], and then executes step 10-3 again;

6. The method of claim 3, wherein said step 12) comprises:

step 12-1), the controller (130) initializes parameters including: initializing the parameter quantity N and a parameter matrix P of the intermediate frequency filter to be tested according to the model of the tuner (110), wherein N is 0, and Pb is P [ N ]; wherein the length of P is N, P0 is default parameter, Pb is optimum parameter, N is circulation variable;

step 12-2), the controller (130) initializes parameters including: let Ea equal to E, let Eb equal to Ea, where E is the error rate in the error code information, Ea, Eb both represent temporary local variables;

step 12-3), the controller (130) assigns values to the variables, and let Ea be E;

step 12-5), the controller (130) updates the variable, and enables Eb to be Ea and Pb to be P;

step 12-7), the controller (130) updates the variable to n +1, then sends a command to configure the intermediate frequency filter in the tuner (110) to P [ n ], and then re-executes step 12-3);

7. The method of claim 3, wherein said step 14) comprises:

step 14-1), the controller (130) initializes parameters including: initializing a parameter quantity N and a parameter matrix P of a baseband filter to be tested, wherein N is 0, and Pb is Pn; wherein the length of P is N, P0 is default parameter, Pb is optimum parameter, N is circulation variable;

step 14-2), the controller (130) initializes parameters including: let Ea equal to E, let Eb equal to Ea; wherein E is the error rate in the error code information, Ea and Eb both represent temporary local variables;

step 14-3), the controller (130) assigns a value to the variable, and let Ea be E;

step 14-5), the controller (130) updates the variable, and enables Eb to be Ea and Pb to be P;

step 14-7), the controller (130) updates the variable, makes n equal to n +1, sends a command to enable the configuration of the baseband filter in the signal processing unit (121) to be P [ n ], and then re-executes step 14-3);