JP2023033974A - Receiving device and noise elimination method - Google Patents

Abstract

To efficiently eliminate noises.SOLUTION: A receiving device performs diversity synthesis of broadcast waves received on both a first tuner and a second tuner. The receiving device includes an estimation unit and an elimination unit. The estimation unit estimates noises included in broadcast waves received on the first tuner on the basis of a reception signal on the second tuner set to a reception frequency where there is no broadcast wave. The elimination unit eliminates noises estimated by the estimation unit from the broadcast waves received by the first tuner.SELECTED DRAWING: Figure 1

Description

The present invention relates to a receiver and a noise elimination method.

2. Description of the Related Art Conventionally, there are receivers that remove noise components from received broadcast waves. For example, a technology for removing noise components from broadcast waves using a noise signal received by a noise pick antenna provided separately from an antenna for receiving broadcast waves has been proposed (for example, Patent Document 1 reference).

JP 2018-56816 A

However, since the conventional technology requires a noise pick antenna, there is room for improvement in terms of improving the efficiency of noise removal.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a receiving apparatus and a noise removing method capable of efficiently removing noise.

In order to solve the above-described problems and achieve the object, a receiver according to the present invention is a receiver for diversity-combining broadcast waves received by both a first tuner and a second tuner. and a removal unit. The estimation unit estimates noise contained in the broadcast wave received by the first tuner based on the reception signal of the second tuner set to a reception frequency where there is no broadcast wave. The removal section removes the noise estimated by the estimation section from the broadcast wave received by the first tuner.

According to the present invention, noise can be removed efficiently.

FIG. 1 is a diagram showing an overview of the noise removal method. FIG. 2 is a block diagram of a receiver according to the first embodiment. 3A is a schematic diagram illustrating an example of processing by an estimation unit according to the first embodiment; FIG. 3B is a schematic diagram illustrating an example of processing by an estimation unit according to the first embodiment; FIG. 3C is a schematic diagram illustrating an example of processing by an estimation unit according to the first embodiment; FIG. FIG. 4 is a flow chart showing a processing procedure executed by the receiving device according to the first embodiment. FIG. 5 is a block diagram of a receiver according to the second embodiment. FIG. 6 is a diagram illustrating an example of processing by an estimating unit according to the second embodiment; FIG. 7 is a flow chart showing the processing procedure executed by the receiving device according to the second embodiment. FIG. 8 is a block diagram of a receiver according to the third embodiment.

Hereinafter, embodiments of a receiving device and a noise removal method disclosed in the present application will be described in detail with reference to the accompanying drawings. In addition, this invention is not limited by embodiment shown below.

(First embodiment)
First, the outline of the noise removal method according to the embodiment will be described with reference to FIG. FIG. 1 is a diagram showing an overview of the noise removal method. Note that the noise removal method according to the embodiment is executed, for example, by the receiving device 10 described later with reference to FIG. For example, the receiving device 10 is a receiving device that receives various broadcast waves such as digital radio and one-segment broadcasting.

By the way, when a receiving device is mounted on a vehicle, for example, an in-vehicle device mounted on the vehicle may become a noise source and cause noise to be superimposed on broadcast waves received by the receiving device. For example, some conventional technologies include a pickup antenna for detecting noise in addition to an antenna for receiving broadcast waves.

However, in this case, there is a risk of an increase in the cost of the product and an increase in the size of the product due to the extra provision of the pickup antenna, and there is room for improvement in terms of efficiency.

Therefore, in the noise elimination method according to the embodiment, noise is detected by one tuner of a diversity receiver that diversity-synthesizes broadcast waves received by a plurality of tuners.

For example, as shown in FIG. 1, the noise elimination method according to the embodiment uses a first tuner C1 connected to a first antenna A1 and a second tuner C2 connected to a second antenna A2.

As shown in FIG. 1, for example, the first tuner C1 is set to the reception channel frequency of broadcast waves, and the second tuner C2 is set to the noise detection frequency for detecting noise. For example, a broadcast wave received by the first tuner C1 is converted into a first received signal St1 by the first tuner C1. The first received signal St1 here is a signal in which noise is superimposed on a signal related to broadcast waves.

Also, the noise detection frequency is a frequency different from the reception channel frequency, for example, a frequency without broadcast waves. For example, the noise detection frequency is a frequency in the vicinity of the reception channel frequency, and is preferably a frequency with high noise reception sensitivity. For this reason, in the noise removal method according to the embodiment, the reception frequency of the second tuner C2 may be appropriately adjusted, and the reception frequency with good noise reception sensitivity may be used as the noise detection frequency.

For example, the second tuner C2 receives noise corresponding to the noise detection frequency and converts it into a second received signal St2. Then, in the noise removal method according to the embodiment, noise contained in the first received signal St1 is estimated from the second received signal St2 (step S1).

For example, in the noise removal method according to the embodiment, when the noise source is a DC/DC converter, noise with a constant frequency interval is generated. Estimate the noise.

In the example shown in FIG. 1, the peak P is detected from the second received signal St2 of the second tuner C2, and the frequency interval of the peak P is specified. Subsequently, among the plurality of frequencies arranged at the specified frequency intervals, those included in the reception frequency band of the reception channel frequency are estimated as the frequencies of the noise N. FIG.

After that, in the noise removal method according to the embodiment, the noise N is removed from the first received signal St1 using, for example, a noise replica Sn that reproduces the estimated noise N (step S2). As a result, the output signal Sb in which the noise replica Sn is removed from the first received signal St1 can be generated. Note that noise removal is not limited to the method using the noise replica Sn. A specific example of this point will be described later.

As described above, in the noise removal method according to the embodiment, one tuner among the plurality of tuners of the diversity receiver is used for noise detection. Therefore, according to the noise removal method according to the embodiment, noise can be removed efficiently because there is no need to separately provide a pickup antenna.

Further, in the noise removal method according to the embodiment, after estimating the noise contained in the broadcast wave from the received signal received by the noise detection tuner, the noise of the broadcast wave is removed, so that the noise is not affected by the broadcast wave. , the noise can be estimated accurately.

Next, a configuration example of the receiving device 10 according to the embodiment will be described using FIG. FIG. 2 is a block diagram of the receiver 10 according to the first embodiment. As shown in FIG. 2, the receiver 10 according to the first embodiment includes a first tuner C1, a second tuner C2, an A/D converter 11, an estimator 20, a remover 30, a demodulator and a section 40 .

The receiving device 10 includes, for example, a computer having a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a hard disk drive, an input/output port, and various circuits. The CPU of the computer performs some or all of the following functions by reading and executing programs stored in the ROM, for example.

The first tuner C1 is connected to the first antenna A1 and receives broadcast waves via the first antenna A1. For example, the first tuner C1 receives OFDM (Orthogonal Frequency Division Multiplexing) broadcasting waves. The broadcast wave received by the first tuner C1 is converted from analog to digital signal by the A/D conversion section 11, and then input to the removal section 30 as the first received signal St1.

The second tuner C2 is connected to the second antenna A2 and receives a signal of a predetermined frequency (for example, the noise detection frequency described above) via the second antenna A2. The signal received by the second tuner C2 is converted from analog to digital signal by the A/D converter 11, and then input to the estimator 20 as the second received signal St2.

The estimation unit 20 estimates noise contained in the broadcast wave received by the first tuner C1 based on the reception signal of the second tuner C2 set to a reception frequency where there is no broadcast wave. For example, the estimation unit 20 detects the peak P from the second received signal St2, and estimates the noise N contained in the first received signal St1 based on the detected peak P.

The estimation unit 20 inputs information about the noise N to the removal unit 30 . The information about the noise N here includes, for example, information about the frequency of the noise N and the time of occurrence. The information about the noise N may be information about the noise replica.

Note that, for example, the estimation unit 20 sequentially sets the reception frequency of the second tuner C2 to a plurality of frequencies, and estimates the noise N from the second reception signal St2 of the second tuner C2 set to each frequency. may

In this case, for example, the estimation unit 20 sequentially switches the reception frequency of the second tuner C2, and sets the second tuner C2 to a reception frequency at which the reception sensitivity of the peak P corresponding to the noise N is high. Thereby, the estimation accuracy of the noise N can be improved.

The removal unit 30 removes the noise N estimated by the estimation unit 20 from the broadcast wave received by the first tuner C1. For example, the removing unit 30 removes the noise N from the first received signal St1 of the first tuner C1 based on the information about the noise N received from the estimating unit 20 .

For example, the removal unit 30 removes noise from the broadcast wave when the noise estimated by the estimation unit 20 is within the reception band of the broadcast wave received by the first tuner C1. In other words, when the noise estimated by the estimation unit 20 is not included in the first received signal St1, various processes related to noise removal are omitted.

Accordingly, noise can be appropriately removed from the first received signal St1. For example, when receiving information about the frequency of the noise N as the information about the noise N, the removing unit 30 reduces the weight and reliability of the frequency of the first received signal St1, and reduces the noise N included in the first received signal St1. The noise N is removed from the first received signal St1 by relatively reducing the signal strength of .

Further, when receiving the information about the time of occurrence of the noise N as the information about the noise N, the removal unit 30 suppresses or blocks the output of the first received signal St1 at the time of occurrence. That is, in this case, the removing unit 30 suppresses or blocks the output of the first received signal St1 by using the peak P of the second received signal St2 as a gate signal. Here, suppression means, for example, suppressing the output level (for example, volume) of the first reception signal St1, and blocking means blocking the output of the first reception signal St1, that is, not outputting it. show.

By these processes, the removing unit 30 can generate a broadcast wave in which the noise N is suppressed or removed from the first received signal St1 extracted by the first tuner C1.

The demodulator 40 OFDM demodulates the output signal Sb (see FIG. 1) input from the remover 30, for example. For example, the output signal Sb OFDM-demodulated by the demodulator 40 is output from a display for displaying video or a speaker for outputting audio.

A specific example of the noise N estimation process performed by the estimation unit 20 will now be described with reference to FIGS. 3A to 3C. 3A to 3C are schematic diagrams showing an example of processing by the estimation unit 20. FIG. In the example shown in FIG. 3A, assume that the estimation unit 20 detects a peak P at frequency f1 at the noise detection frequency received by the second tuner C2.

In this case, for example, the estimation unit 20 estimates that noise occurs at frequency f1×n (where n is a natural number) with frequency f1 as a reference. In this case, for example, when the value obtained by multiplying the frequency f1 by an integer (f1×n) is included in the receiving band (receiving channel frequency) of the first tuner C1, the estimating unit 20 determines that the frequency is the noise included in the receiving channel frequency. Assume N frequencies.

In the example shown in the figure, since "2·f1", which is obtained by doubling the frequency f1, exists within the reception channel frequency, it is assumed that the first received signal St1 contains noise N having a frequency of "2·f1". presume. Here, the frequency is f1×n (n is a natural number), but the noise N may be estimated from the peak P as a frequency f1/n (n is a natural number).

In the example of FIG. 3B, as in FIG. 3A, it is assumed that the estimator 20 detects the peak P of frequency f1 at the noise detection frequency received by the second tuner C2. In this case, if the frequency (f1+Δf) obtained by shifting the peak P by the difference Δf between the noise detection frequency and the reception channel frequency is within the range of the reception channel frequency, the estimation unit 20 determines that the first reception signal St1 has Assume that noise N with a frequency of "f1+Δf" is included.

Also, in the example of FIG. 3C, the estimation unit 20 first identifies the timing of the peak P detected at the noise detection frequency. The estimator 20 then estimates the timing as the timing of the noise N contained in the broadcast wave received by the first tuner C1.

That is, in the receiver 10, both the first tuner C1 and the second tuner C2 receive noise generated from the same noise source. to estimate

This makes it possible to accurately estimate the timing at which noise N occurs. For example, in this case, as described above, the removing unit 30 suppresses or cuts off the output of the first received signal St1 using the peak P of the second received signal St2 as a gate signal, thereby removing the noise from the first received signal St1. Remove N.

By these processes, the estimation unit 20 can estimate the noise N with high accuracy. For example, the estimation unit 20 may estimate the noise N by appropriately combining these processes.

Next, a processing procedure executed by the receiving device 10 according to the first embodiment will be described with reference to FIG. FIG. 4 is a flowchart showing a processing procedure executed by the receiving device 10 according to the first embodiment. Note that the processing procedure described below is repeatedly executed by the estimating unit 20 and the removing unit 30 .

As shown in FIG. 4, first, the receiving device 10 acquires the second reception signal St2 of the second tuner C2 set to the noise detection frequency (step S101), and sets the reception ch frequency from the second reception signal St2. The noise N included in the first received signal St1 of the first tuner C1 is estimated (step S102).

Subsequently, the receiving device 10 removes the noise N from the first received signal St1 based on the processing result of step S102 (step S103), and ends the processing.

As described above, the receiving device 10 according to the embodiment is a receiving device 10 that diversity-combines the broadcast waves received by both the first tuner C1 and the second tuner C2. Based on the received signal of the second tuner C2 set to and a removal unit 30 for removing the estimated noise. Therefore, the receiving device 10 according to the embodiment can efficiently remove noise.

(Second embodiment)
Next, the receiver 10A according to the second embodiment will be described with reference to FIGS. 5 to 7. FIG. In addition, below, the same code|symbol is attached|subjected about the already demonstrated structure, and the overlapping description is abbreviate|omitted.

First, a configuration example of a receiving device 10A according to the second embodiment will be described using FIG. FIG. 2 is a block diagram of a receiver 10A according to the second embodiment. A receiving device 10A according to the second embodiment differs from the receiving device 10 already described in the configuration of an estimating section 20A and a removing section 30A, and further includes an adjusting section 50 .

For example, as shown in FIG. 5, the estimator 20A includes an extractor 21 and a generator 22 . For example, the extraction unit 21 separates the second received signal St2 into a pulse noise component and a random noise component, and extracts the pulse noise component from the second received signal St2.

The generator 22 generates a noise replica Sn based on the pulse noise component extracted by the extractor 21 . The generator 22 outputs the generated noise replica Sn to the adjuster 50 .

The adjuster 50 adjusts the gain of the noise replica Sn. For example, the adjustment unit 50 is a so-called adaptive filter, and uses an optimization algorithm such as the LMS (Least Mean Square) algorithm to set filter coefficients of the noise replica Sn input from the estimation unit 20A. Further, the adjustment unit 50 acquires the output signal output from the removal unit 30A and optimizes the filter coefficients.

The removal unit 30A subtracts the noise replica Sn input from the adjustment unit 50 from the first reception signal St1 input from the first tuner C1, thereby generating an output signal in which the noise N is removed from the first reception signal St1. do. The output signal generated by removal section 30A is input to adjustment section 50 together with demodulation section 40 .

Next, a specific example of processing by the estimation unit 20A will be described with reference to FIG. FIG. 6 is a diagram showing an example of processing of the estimation unit 20A according to the second embodiment. As shown in FIG. 6, the extractor 21 of the estimator 20A separates the second received signal St2 into a pulse noise component Pp and a random noise component Pr, and extracts the pulse noise component Pp from the second received signal St2. . Note that a known technique is used for separating the pulse noise component Pp and the random noise component Pr. For example, as illustrated in FIG. 6, random noise has a low level and tends to appear continuously over time, while pulse noise has a high level and tends to appear intermittently. A value averaged over a predetermined period of time can be used as a threshold value, and those exceeding the threshold value can be separated as pulse noise.

In this case, the generator 22 generates the noise replica Sn by, for example, shifting the frequency of the pulse noise component Pp by the difference Δf between the reception channel frequency and the noise detection frequency.

As a result, a noise replica Sn that reproduces even the phase of the pulse noise component Pp can be generated, so that the noise N can be accurately removed from the first received signal St1. Note that the generation unit 22 may use the frequency-shifted version of the pulse noise component Pp extracted by the extraction unit 21 as the noise replica Sn. The noise replica Sn may be obtained by shifting the frequency of the pulse signal generated based on the (predetermined number) averaged values. For example, the generation unit 22 can obtain an average pulse width from a plurality of pulse noises, and generate a new pulse signal having the same level and phase as the original pulse noise and the average pulse width obtained above. I can. Note that the level or phase may be averaged instead of the pulse width, or any two or all of the level/width/phase may be averaged to generate a pulse signal.

Next, a processing procedure executed by the receiving device 10A according to the second embodiment will be described with reference to FIG. FIG. 7 is a flow chart showing a processing procedure executed by the receiving device 10A according to the second embodiment.

As shown in FIG. 7, first, when the receiving device 10A acquires the second received signal St2 (step S201), the noise N included in the first received signal St1 is estimated from the second received signal St2 (step S202). .

Subsequently, the receiver 10A generates a noise replica based on the estimated noise N (step S203), subtracts the noise replica from the first received signal St1 (step S204), and ends the process.

(Third Embodiment)
Next, a receiver 10B according to the third embodiment will be described using FIG. FIG. 8 is a block diagram of a receiver 10B according to the third embodiment. As shown in FIG. 3, the receiver 10B according to the third embodiment sets the first tuner C1 and the second tuner C2 to the reception channel frequencies, respectively, and then sets the subsequent noise detection tuner C3 to the noise detection frequency. set.

That is, in this case, the first tuner C1 and the second tuner C2 receive signals at both the reception frequency of broadcast waves and the reception frequency without broadcast waves. The noise detection tuner C3 is connected to either the first tuner C1 or the second tuner C2 by a switch SW. Also, in this case, for example, the first tuner C1 and the second tuner C2 receive broadcast waves and noise, respectively. Therefore, it is preferable that the A/D converter 11 be a wide-area A/D converter capable of converting frequencies in a wider range.

For example, from the received signals (first received signal St1 and second received signal St2) output from the A/D converter 11, a BPF (Band Pass Filter) 15 extracts only broadcast signals in a specific frequency band.

For example, the estimating unit 20B switches the switch SW1 to estimate noise from each of the first received signal St1 and the second received signal St2, thereby determining which of the first tuner C1 and the second tuner C2 has noise. determines whether the reception sensitivity of is high. That is, of the first antenna A1 and the second antenna A2, the antenna that is easier to detect noise is used as the antenna for noise detection.

Then, the estimating section 20B fixes the switch SW so that the received signal is input from the tuner with high reception sensitivity to noise. When the switch SW is fixed, the estimator 20B estimates the noise N contained in the first received signal St1 and the second received signal St2 from the signal input from the noise detection tuner C3 via the BPF 15, and determines the estimated noise. Generate noise replicas based on

The noise replicas generated by the estimating section 20B are input to the removing sections 30A via the adjusting section 50, respectively. Then, the removing unit 30A inputs to the demodulating unit 40 an output signal obtained by removing the noise replica from the first received signal St1 or the second received signal St2. Such output signals are demodulated by the demodulator 40, diversity-synthesized by the synthesizer 60, and output to a speaker or display (not shown).

Thus, in the receiver 10B according to the third embodiment, both the first tuner C1 and the second tuner C2 receive broadcast waves, and the noise detection tuner C3 is set to the noise detection frequency.

Therefore, the receiver 10B according to the third embodiment can appropriately remove noise even when broadcast waves are received by both the first tuner C1 and the second tuner C2.

By the way, in the above-described embodiment, the case where the receiving device 10 is mounted on a vehicle has been described, but the present invention is not limited to this. Also, the configurations of the first to third embodiments described above may be used in combination as appropriate.

Further effects and modifications can be easily derived by those skilled in the art. Therefore, the broader aspects of the invention are not limited to the specific details and representative embodiments so shown and described. Accordingly, various changes may be made without departing from the spirit or scope of the general inventive concept defined by the appended claims and equivalents thereof.

10, 10A, 10B receiver 20, 20A, 20B estimator 30, 30A remover C1 first tuner C2 second tuner C3 noise detection tuner A1 first antenna A2 second antenna

Claims (9)

A receiver for diversity combining broadcast waves received by both a first tuner and a second tuner,
an estimating unit for estimating noise contained in the broadcast wave received by the first tuner based on the received signal of the second tuner set to a reception frequency where there is no broadcast wave;
and a removing unit that removes the noise estimated by the estimating unit from the broadcast wave received by the first tuner. The estimation unit
A peak frequency contained in the received signal of the second tuner is shifted by a difference between a first frequency that is the reception frequency of the first tuner and a second frequency that is the reception frequency of the second tuner. 2. The receiving apparatus according to claim 1, wherein the value is estimated as the frequency of the noise. The estimation unit
When the frequency obtained by multiplying or dividing the peak frequency contained in the received signal of the second tuner by an integer is included in the reception frequency band of the broadcast wave received by the first tuner, the frequency is included in the noise. The receiving device according to claim 1, wherein the frequency is estimated. The estimation unit
identifying frequency intervals of peaks included in the received signal of the second tuner, and selecting, among a plurality of frequencies arranged at the frequency intervals, those included in the reception frequency band of the broadcast wave received by the first tuner; The receiving apparatus according to claim 1, wherein the frequency is estimated as the frequency of the noise. The estimation unit
setting a plurality of second frequencies, which are reception frequencies of the second tuner, and specifying the frequency interval from a peak frequency included in the reception signal of the second tuner set to each of the second frequencies. The receiving device according to claim 4, wherein The estimation unit
2. The timing of the pulse noise included in the received signal of the second tuner is specified, and the timing is estimated as the timing of the pulse noise included in the broadcast wave received by the first tuner. 2. The receiving device according to . The removal unit
7. The receiving apparatus according to claim 6, wherein output of said broadcast wave received by said first tuner is suppressed or cut off in accordance with said timing. The estimation unit
extracting pulse noise contained in the received signal received by the second tuner; The receiving apparatus according to claim 1, wherein a signal shifted by a difference from a certain second frequency is estimated as the noise. A noise removal method using a receiver that diversity-synthesizes broadcast waves received by both a first tuner and a second tuner,
an estimating step of estimating noise contained in the broadcast wave received by the first tuner based on the received signal of the second tuner set to a reception frequency where there is no broadcast wave;
and a removing step of removing the noise estimated by the estimating step from the broadcast wave received by the first tuner.

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