JP2016154295A - Diversity receiving device and diversity receiving method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the quality of a reproduction signal while effectively utilizing properties of adaptive filtering and composite diversity.SOLUTION: A first reproduction signal generation part 131performs adaptive filtering on a signal IFDto generate a signal FLDof which the level is fixed. A second reproduction signal generation part 131performs adaptive filtering on a signal IFDto generate a signal FLDwhich fixes the level of a signal obtained by performing weighting addition on a signal DFD obtained by the adaptive filtering and the signal FLD. Based on an error ERreflected with a level difference between the level of the signal FLDand a reference level and an error ERreflected with a level difference between the level of the signal FLDand the reference level, a control unit 190A controls a selection of which one of the signal FLDand the signal FLDis to be used as a reproduction signal.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a diversity receiving device, a diversity receiving method, a diversity receiving program, and a recording medium on which the diversity receiving program is recorded.

  2. Description of the Related Art Conventionally, receiving apparatuses that are mounted on a moving body such as a vehicle and receive broadcast waves have been widely used. In such a receiving apparatus, there is a problem that the reproduction quality of the broadcast content is deteriorated due to a multipath phenomenon or the like caused by the reflection of the broadcast wave on the wall of the surrounding building. In order to cope with this problem, it has been proposed to employ an adaptive filter technique (see Non-Patent Document 1).

  There has also been proposed a technique of a diversity receiving apparatus that combines such an adaptive filter technique and a combining diversity technique (see Patent Document 1: hereinafter referred to as “conventional example”). As a technique of this conventional example, (i) a technique for synthesizing a plurality of signals after the adaptive filtering processing is performed after performing adaptive filtering processing independent of each other on the reception signals of the plurality of antennas, And (ii) combining the plurality of signals subjected to the filtering process after performing the filtering process on the reception signals of the plurality of antennas, and receiving each of the plurality of antennas based on the combined signal. A technique for adapting a filtering process on a signal is disclosed.

JP 2004-040424 A

Itami et al., Television Society Journal, Vol. 42, no. 5 (1988), pp. 5-8. 478-483

  In the conventional technology described above, adaptive filtering processing and combining diversity are performed with equal weights at respective points in time for signals received by a plurality of antennas. As a result, for example, the quality of the synthesized signal in a period in which there is a large difference in the quality of the received signal between the antennas is lower than the quality of the received signal with higher received quality.

  For this reason, there is a need for a technique that can improve the quality of a signal for reproduction while utilizing the characteristics of adaptive filtering processing and synthesis diversity. Meeting this requirement is one of the problems to be solved by the present invention.

  The invention according to claim 1 is a first frequency conversion unit that generates a first frequency conversion signal by performing frequency conversion of a broadcast signal of a channel that is received and selected by a first antenna; and A second frequency conversion unit that receives a different second antenna and performs frequency conversion of the broadcast signal of the selected channel to generate a second frequency conversion signal; and first to the first frequency conversion signal A first reproduction signal generation unit that performs adaptive filtering processing to generate a first reproduction signal with a constant level; and performs second adaptive filtering processing on the second frequency conversion signal to perform the second adaptive filtering. A second reproduction signal generator for generating a second reproduction signal in which the level of a signal obtained by weighting and adding the signal obtained by the processing and the first reproduction signal is constant; and the first reproduction signal A control unit that controls which of the first reproduction signal and the second reproduction signal is selected based on the signal quality and the signal quality of the second reproduction signal. Diversity receiver.

  The invention according to claim 7 is a first frequency conversion unit that generates a first frequency converted signal by performing frequency conversion of a broadcast signal of a channel received and received by the first antenna; and the first antenna; Receiving a different second antenna, and performing a frequency conversion of the broadcast signal of the selected channel to generate a second frequency conversion signal, and a diversity reception apparatus used in a diversity reception device comprising: A first reproduction signal generation step of performing a first adaptive filtering process on the first frequency conversion signal to generate a first reproduction signal with a constant level; and the second frequency conversion signal. Is subjected to a second adaptive filtering process, and the signal obtained by weighted addition of the signal obtained by the second adaptive filtering process and the first reproduction signal is recorded. A second reproduction signal generating step for generating a second reproduction signal with a constant level; and based on the signal quality of the first reproduction signal and the signal quality of the second reproduction signal. And a control step of controlling which one of the reproduction signal and the second reproduction signal is to be selected.

  According to an eighth aspect of the present invention, there is provided a diversity reception program that causes a computer included in the diversity reception apparatus to execute the diversity reception method according to the seventh aspect.

  The invention described in claim 9 is a recording medium in which the diversity reception program according to claim 8 is recorded so as to be readable by a computer included in the diversity reception apparatus.

It is a block diagram for demonstrating the schematic structure of the diversity receiver of 1st Embodiment of this invention. It is a block diagram which shows the structure of the signal processing unit of FIG. FIG. 3 is a block diagram illustrating a configuration of a first reproduction signal generation unit in FIG. 2. It is a block diagram which shows the structure of the digital filter part of FIG. FIG. 3 is a block diagram illustrating a configuration of a second reproduction signal generation unit in FIG. 2. It is a block diagram for demonstrating the schematic structure of the diversity receiver of 2nd Embodiment of this invention. It is a block diagram which shows the structure of the signal processing unit of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description and drawings, the same or equivalent elements are denoted by the same reference numerals, and redundant description is omitted.

[First Embodiment]
First, a first embodiment of the present invention will be described with reference to FIGS.

<Configuration>
FIG. 1 is a block diagram illustrating a schematic configuration of a diversity receiver 100A according to the first embodiment. As shown in FIG. 1, diversity receiver 100A includes antennas 110 _M and 110 _S , RF processing units 120 _M and 120 _S , signal processing unit 130A, and stereo demodulation unit 140. The diversity receiver 100A includes sound output units 160 _L and 160 _R , an input unit 170, and a control unit 190A.

The antenna 110 _M described above receives broadcast waves. Then, the reception result by the antenna 110 _M is sent to the RF processing unit 120 _M as a reception signal RFS _M.

The antenna 110 _S receives broadcast waves in the same manner as the antenna 110 _M. Then, the reception result by the antenna 110 _S is sent to the RF processing unit 120 _S as a reception signal RFS _S.

The RF processing unit 120 _M receives the reception signal RFS _M transmitted from the antenna 110 _M described above. Then, the RF processing unit 120 _M performs frequency conversion for converting the frequency of the pilot signal component of the broadcast wave in the reproduction channel into a predetermined intermediate frequency in accordance with the channel selection command CSL _M sent from the control unit 190A. The signal IFD _M that has been subjected to is generated. The signal IFD _M generated in this way is sent to the signal processing unit 130A.

Here, the RF processing unit 120 _M includes an input filter, a high-frequency amplifier (RF AMP: Radio Frequency-Amplifier), and a band-pass filter (hereinafter also referred to as “RF filter”). Further, the RF processing unit 120 _M includes a mixer (mixer), an intermediate frequency filter (hereinafter also referred to as “IF filter”), and an intermediate frequency amplifier (IF AMP: Intermediate Frequency-Amplifier). Further, the RF processing unit 120 _M includes a local oscillation circuit (OSC) and an AD converter (Analogue to Digital Converter: ADC).

The input filter is a high-pass filter that blocks low-frequency components of the reception signal RFS _M transmitted from the antenna 110 _M. The high frequency amplifier amplifies the signal that has passed through the input filter.

  The RF filter selectively passes a signal in a specific frequency range among signals output from the high-frequency amplifier. The mixer mixes the signal that has passed through the RF filter and the local oscillation signal supplied from the local oscillation circuit.

The IF filter selects and passes a signal in a predetermined intermediate frequency range among the signals output from the mixer. The intermediate frequency amplifier amplifies the signal that has passed through the IF filter. Then, AD converter converts the amplified result of the intermediate frequency amplifier into a digital signal, as the signal IFD _M, and sends to the signal processing unit 130A.

The local oscillation circuit includes an oscillator that can control the oscillation frequency by voltage control or the like. This local oscillation circuit generates a local oscillation signal having a frequency corresponding to a channel to be selected in the RF processing unit 120 _M in accordance with the channel selection command CSL _M supplied from the control unit 190 A, and supplies the local oscillation signal to the mixer.

The RF processing unit 120 _S receives the reception signal RFS _S sent from the antenna 110 _S. Then, the RF processing unit 120 _S performs frequency conversion for converting the frequency of the pilot signal component of the broadcast wave in the reproduction channel into a predetermined intermediate frequency in accordance with the channel selection command CSL _S sent from the control unit 190A. A signal IFD _S is generated. The signal IFD _S thus generated is sent to the signal processing unit 130A.

The RF processing unit 120 _S is configured in the same manner as the RF processing unit 120 _M described above. In the first embodiment, the channel selection command CSL _S and the channel selection command CSL _M are channel selection commands that designate the same channel.

It said signal processing unit 130A may, RF processing unit 120 signals IFD sent from _{M M,} and receives a signal IFD _S sent from the RF processing unit 120 _S. Subsequently, the signal processing unit 130A performs signal processing on the signal IFD _M and the signal IFD _S. Then, the signal processing unit 130A sends the signal selected according to the selection designation SLC sent from the control unit 190A to the stereo demodulation unit 140 as the signal CSD.

Further, the signal processing unit 130A sends the errors ER ₁ and ER ₂ obtained in the signal processing described above to the control unit 190A. The configuration of the signal processing unit 130A will be described later.

The stereo demodulation unit 140 described above receives the signal CSD sent from the signal processing unit 130A. Then, the stereo demodulation unit 140 performs stereo demodulation processing including separation processing on the signal CSD to generate output audio signals AOD _L and AOD _R. The output audio signals AOD _L and AOD _R thus generated are sent to the sound output units 160 _L and 160 _R.

The sound output unit 160 _L includes a DA (Digital to Analogue) converter, an electronic volume, a speaker, and the like. The sound output unit 160 _L receives the output audio signal AOD _L sent from the stereo demodulation unit 140 and the volume designation VLC sent from the control unit 190A. Then, the sound output unit 160 _L outputs sound corresponding to the output sound signal AOD _L at a sound volume according to the sound volume designation VLC.

Similar to the sound output unit 160 _L , the sound output unit 160 _R includes a DA converter, an electronic volume, a speaker, and the like. The sound output unit 160 _R receives the output audio signal AOD _R sent from the stereo demodulation unit 140 and the volume designation VLC sent from the control unit 190A. Then, the sound output unit 160 _R outputs sound corresponding to the output sound signal AOD _R at a sound volume according to the sound volume designation VLC.

  Said input unit 170 is comprised by the remote input device etc. which are provided with the key part provided in the main-body part of the diversity receiver 100A, and / or a key part. Here, as a key part provided in the main body, a touch panel provided in a display unit (not shown) can be used. In addition, it can replace with the structure which has a key part, or can also employ | adopt the structure which inputs with a sound using a voice recognition technique in combination. An input result to the input unit 170 is sent to the control unit 190A as input data IPD. By operating this input unit 170, the user can input designation of a reproduction channel, designation of output volume, and the like.

The control unit 190A controls the overall operation of the diversity receiver 100A. When the control unit 190A is notified as the input data IPD of the playback channel to be played back of the broadcast sound input to the input unit 170, the control unit 190A selects the playback channel selection commands CSL _M and CSL according to the specification of the playback channel. Generate _S. Then, the control unit 190A sends the generated channel selection instructions CSL _M and CSL _S to the RF processing units 120 _M and 120 _S.

Further, when the designation of the output volume input to the input unit 170 is notified as the input data IPD, the control unit 190A generates a volume designation VLC according to the designation of the output volume. Then, the control unit 190A sends the generated volume designation VLC to the sound output units 160 _L and 160 _R.

Further, the control unit 190A receives the errors ER ₁ and ER ₂ sent from the signal processing unit 130A. Then, the control unit 190A generates a selection designation SLC based on the errors ER ₁ and ER ₂ and sends the generated selection designation SLC to the signal processing unit 130A. The generation process of the selection designation SLC by the control unit 190A will be described later.

<< Configuration of Signal Processing Unit 130A >>
Next, the configuration of the signal processing unit 130A described above will be described. As illustrated in FIG. 2, the signal processing unit 130 </ b> A includes a first reproduction signal generation unit 131 ₁ , a second reproduction signal generation unit 131 ₂ , a selection unit 132, and a detection unit 133.

The first reproduction signal generator 131 ₁ receives the signal IFD _M sent from the RF processing unit 120 _M. The first reproduced signal generating unit 131 ₁ performs adaptive filtering on the signal IFD _M, to generate a signal FLD ₁ was constant the level. The signal FLD ₁ thus generated is sent to the second reproduction signal generator 131 ₂ and the selector 132.

The first reproduced signal generating unit 131 ₁ transmits the error ER ₁ obtained during the adaptive filtering for the signal IFD _M to the control unit 190A. Details of the configuration of the first reproduction signal generator 131 ₁ will be described later.

Second reproduction signal generating section 131 ₂ of the receive signal IFD _S sent from the RF processing unit 120 _S. Then, the second reproduction signal generator 131 ₂ performs an adaptive filtering process on the signal IFD _S and makes the level of the signal obtained by weighted addition of the signal obtained by the adaptive filtering process and the signal FLD ₁ constant. A signal FLD ₂ is generated. The signal FLD ₂ generated in this way is sent to the selection unit 132.

Further, the second reproduction signal generator 131 ₂ sends the error ER ₂ obtained in the adaptive filtering process for the signal IFD _S to the control unit 190A. The details of the second reproduction signal generator 131 ₂ configuration will be described later.

The selection unit 132 receives the signal FLD ₁ sent from the first reproduction signal generation unit 131 ₁ and the signal FLD ₂ sent from the second reproduction signal generation unit 131 ₂ . Then, the selection unit 132 selects either the signal FLD ₁ or the signal FLD _{2 in} accordance with the selection designation SLC sent from the control unit 190A, and sends the selected signal to the detection unit 133 as the signal SLD.

  The detection unit 133 receives the signal SLD sent from the selection unit 132. And the detection part 133 performs a detection process with respect to the signal SLD, and produces | generates the signal CSD. The signal CSD generated in this way is sent to the stereo demodulation unit 140.

(Configuration of first reproduction signal generator 131 ₁ )
Next, the configuration of the first reproduction signal generator 131 ₁ described above will be described.

As shown in FIG. 3, the first reproduction signal generation unit 131 ₁ includes a digital filter unit 220 ₁ . In addition, the first reproduction signal generation unit 131 ₁ includes an error calculation unit 230 ₁ and a coefficient update unit 240 ₁ .

Digital filtering unit 220 ₁ of the above, in the first embodiment, is configured as an FIR (Finite Impulse Response) filter. The digital filter unit 220 ₁ receives the signal IFD _M sent from the RF processing unit 120 _M. Then, the digital filter unit 220 ₁ performs a filtering operation according to the coefficient designation CEF ₁ sent from the coefficient update unit 240 ₁ to generate a signal FLD ₁ . The signal FLD ₁ generated in this way is sent to the error calculation unit 230 ₁ , the coefficient update unit 240 ₁ , the second reproduction signal generation unit 131 _2, and the selection unit 132.

Here, the configuration of the digital filter unit 220 _1. As shown in FIG. 4, the digital filter unit 220 ₁ includes (M−1) delay units 221 _{1 to} 221 _M−1 and M coefficient multipliers 222 _{0 to} 222 _M−1. Yes. The digital filter unit 220 ₁ includes an adder 223.

Each of the delay devices 221 _j (j = 1 to M−1) delays the input signal X _j−1 (T) by a unit delay time τ and outputs it as a signal X _j (T + τ). Here, the signal X ₀ (T) is the signal IFD _M sent from the RF processing unit 120 _M. As a result, the relationship between the signal X _j (T) and the signal X ₀ (T) is expressed by the following equation (1).
X _j (T) = X ₀ (T−j · τ) (1)

In the first embodiment, each of the delay devices 221 _j samples the signal X _j−1 (T) in synchronization with a reference clock (not shown) whose period is a unit delay time τ, and outputs the signal X _j (T + τ). ). For this reason, during the unit delay time τ, the sampling result is held in the delay unit 221 _j and is output. Here, the unit delay time τ is ¼ of the period of the carrier component included in the signal X ₀ (T).

The signal X _j (T) generated by the delay unit 221 _j is sent to the coefficient multiplier 222 _j . A signal X ₀ (T) is sent to the coefficient multiplier 222 ₀ .

Each of the coefficient multipliers 222 _m (m = 0 to M−1) includes the signal X _m (T) and the tap coefficient K _m (T) in the coefficient designation CEF ₁ sent from the coefficient updating unit 240 _1. Receive. The coefficient multiplier 222 _m multiplies the signal X _m (T) by the tap coefficient K _m (T). The result of this multiplication is sent to the adder 223.

The adder 223 performs multiplication results [X ₀ (T) · K ₀ (T)] to [X _M-1 (T) · K _M-1 (T) by the coefficient multipliers 222 _{0 to} 222 _M−1. ]. Then, the adder 223 calculates the signal Y (T) by the following equation (2).
Y (T) = X ₀ (T) · K ₀ (T) +... + X _M-1 (T) · K _M-1 (T) (2)

The signal Y (T) calculated in this way is sent as the signal FLD ₁ to the error calculation unit 230 ₁ , the coefficient update unit 240 ₁ , the second reproduction signal generation unit 131 _2, and the selection unit 132.

Returning to FIG. 3, the error calculation unit 230 ₁ receives the signal FLD ₁ sent from the digital filter unit 220 ₁ . Subsequently, the error calculation unit 230 ₁ based on the signal FLD _1, calculates the envelope signal of the signal FLD _1. Based on the calculated envelope signal and the reference level A held inside, the error calculation unit 230 ₁ calculates the level of the envelope signal (and thus the signal FLD ₁ ) and the reference level A. An error ER ₁ (= ε (T)) reflecting the difference is calculated. The error ER ₁ calculated in this way is sent to the coefficient updating unit 240 ₁ and the control unit 190A.

Note that the absolute value of error ER ₁ reflects the signal quality of signal FLD ₁ . Here, extent absolute value of the error ER ₁ is small, the signal quality of the signal FLD ₁ is high. This is because the correction amount for the signal IFD _M by the filtering process performed by the digital filter unit 220 ₁ is small, and it can be said that the reception quality when the broadcast wave of the reproduction channel is received by the antenna 110 _M is high.

The coefficient updating unit 240 ₁ receives the signal IFD _M (= X ₀ (T) = X _m (T−m · τ)) sent from the RF processing unit 120 _M and the signal sent from the digital filter unit 220 _1. FLD ₁ (= Y (T)) and the error ER ₁ (= ε (T)) sent from the error calculator 230 ₁ are received. The coefficient updating unit 240 _{1 then} generates a new tap coefficient based on the signal IFD _M (= X ₀ (T)), the signal FLD ₁ (= Y (T)), and the error ER ₁ (= ε (T)). K _m (T + τ) is calculated. The new tap coefficient K _m (T + τ) calculated in this way is sent to the digital filter unit 220 ₁ as coefficient designation CEF ₁ .

In the first embodiment, the algorithm disclosed in “2.1” of Non-Patent Document 1 described above is employed, and the error ER ₁ (= ε) is calculated in the error calculation unit 230 ₁ and the coefficient update unit 240 ₁ . (T)) and a new tap coefficient K _m (T + τ) are calculated.

(Second configuration of the reproducing signal generator 131 ₂₎
Next, a description will be given of the second reproducing signal generator 131 ₂ structure described above.

As shown in FIG. 5, the second reproduction signal generation unit 131 ₂ includes a digital filter unit 220 ₂ , an error calculation unit 230 _2, and a coefficient update unit 240 ₂ . The second reproduced signal generating unit 131 ₂ includes a multiplication unit 250, an addition unit 260.

The digital filter unit 220 ₂ is configured in the same manner as the above-described digital filter unit 220 ₁ (see FIG. 4). The digital filter section 220 ₂ receives the signal IFD _S sent from the RF processing unit 120 _S. Then, the digital filter unit 220 ₂ performs a filtering operation according to the coefficient designation CEF ₂ sent from the coefficient update unit 240 ₂ to generate a signal DFD. The signal DFD generated in this way is sent to the adding unit 260.

The multiplication unit 250 receives the signal FLD ₁ sent from the first reproduction signal generation unit 131 ₁ . Multiplier 250 multiplies signal FLD ₁ by a predetermined constant α. The multiplication result by the multiplication unit 250 is sent to the addition unit 260 as a signal MYD.

  In the first embodiment, the constant α is “½”.

The above adder 260, the signal sent from the digital filter section 220 ₂ DFD, and receives a signal MYD sent from multiplication section 250. Then, the adding unit 260 adds the signal DFD and the signal MYD. The addition result by the adder 260 is sent as a signal FLD ₂ to the error calculator 230 ₂ , the coefficient updater 240 _2, and the selector 132.

The error calculation unit 230 ₂ is configured in the same manner as the error calculation unit 230 ₁ described above. The error calculation unit 230 ₂ receives the signal FLD ₂ sent from the addition unit 260. Subsequently, the error calculation unit 230 ₂ based on the signal FLD _2, calculates the envelope signal of the signal FLD _2. Then, based on the calculated envelope signal and the reference level A held therein, the error calculation unit 230 ₂ calculates the level of the envelope signal (and thus the signal FLD ₂ ) and the reference level A. An error ER ₂ reflecting the difference is calculated. The error ER ₂ calculated in this way is sent to the coefficient updating unit 240 ₂ and the control unit 190A.

Note that the absolute value of the error ER ₂ reflects the signal quality of the signal FLD ₂ . Here, the smaller the absolute value of the error ER _2, the higher the signal quality of the signal FLD ₂ . When the absolute value of the error ER ₂ is greater than the absolute value of the error ER _1, the signal IFD for generating the signals FLD ₂ in consideration of _S, signal FLD ₁ only the signal quality following signals obtained by FLD ₂ It can be said that it has become.

The coefficient updating unit 240 ₂ is configured in the same manner as the coefficient updating unit 240 ₁ described above. The coefficient updating unit 240 _2, the signal IFD _S sent from the RF processing unit 120 _S, signal FLD ₂ sent from the adder 260, and receives the error ER ₂ sent from the error calculation unit 230 _2. Then, the coefficient updating unit 240 ₂ calculates a new tap coefficient K _m (T + τ) based on the signal IFD _S , the signal FLD _2, and the error ER ₂ . The new tap coefficient K _m (T + τ) calculated in this way is sent to the digital filter unit 220 ₂ as coefficient designation CEF ₂ .

As described above, the error calculation unit 230 ₂ is configured in the same manner as the error calculation unit 230 ₁ and the coefficient update unit 240 ₂ is configured in the same manner as the coefficient update unit 240 ₁ , so that the signal FLD ₁ The level and the level of the signal FLD ₂ are made identical.

[Operation]
Next, the operation of the diversity receiving apparatus 100A configured as described above will be described mainly focusing on the signal processing performed by the signal processing unit 130A and the signal selection control processing performed by the control unit 190A.

As a premise, the diversity receiving apparatus 100A has started a broadcast receiving operation, and the control unit 190A sets the reproduction channel to the RF processing units 120 _M and 120 _S according to the channel selection designation input to the input unit 170. It is assumed that As a result, from the RF processing units 120 _M and 120 _S , signals IFD _M and IFD _S corresponding to the reception results of the broadcast waves of the reproduction channel by the antennas 110 _M and 110 _S are sent to the signal processing unit 130A. (See FIG. 1).

In addition, it is assumed that the control unit 190A sends the volume designation VLC generated according to the designation of the output volume input to the input unit 170 to the sound output units 160 _L and 160 _R (see FIG. 1).

In such a state, signal processing by the signal processing unit 130A is executed. In such signal processing, the signal processing unit 130A, a first reproduction signal generating unit 131 ₁ receives a signal IFD _M sent from the RF processing unit 120 _M. Subsequently, the digital filter unit 220 ₁ , the error calculation unit 230 _1, and the coefficient update unit 240 ₁ in the first reproduction signal generation unit 131 ₁ cooperate to perform adaptive filtering processing on the signal IFD _M as described above. The signal FLD ₁ with a constant level is generated. The first reproduced signal generating unit 131 _1, and sends the generated signal FLD ₁ to the second reproducing signal generator 131 ₂ and the selector 132, the error ER ₁ calculated by the error calculating unit 230 ₁ The data is sent to the control unit 190A (see FIG. 3).

Further, the signal processing unit 130A, the second reproduced signal generating unit 131 ₂ is subjected to signal IFD _S sent from the RF processing unit 120 _S. In addition, the second reproduction signal generator 131 ₂ receives the signal FLD ₁ sent from the first reproduction signal generator 131 ₁ (see FIG. 5).

Subsequently, the digital filter unit 220 ₂ , the error calculation unit 230 ₂ , the coefficient update unit 240 ₂ , the multiplication unit 250 and the addition unit 260 in the second reproduction signal generation unit 131 ₂ cooperate as described above, and the signal IFD _S Is subjected to adaptive filtering processing, and a signal FLD _{2 in} which the level of the signal obtained by weighted addition of the signal DFD obtained by the adaptive filtering processing and the signal FLD ₁ is made constant is generated. The second reproduction signal generating section 131 _2, and sends the generated signal FLD ₂ to selector 132, and sends the error ER ₂ calculated by the error calculating unit 230 ₂ to the control unit 190A (see FIG. 5) .

Upon receiving the error ER ₁ sent from the first reproduction signal generator 131 ₁ and the error ER ₂ sent from the second reproduction signal generator 131 ₂ , the control unit 190A determines the absolute value of the error ER ₂ . It is determined whether or not is larger than a predetermined difference than the absolute value of the error ER ₁ . Then, if the result of the determination is affirmative, the control unit 190A generates a selection designated SLC specifying signal FLD _1. Then, the control unit 190A sends the generated selection designation SLC to the signal processing unit 130A (see FIG. 2).

On the other hand, if the result of the determination is negative, the control unit 190A generates a selection designated SLC specifying signal FLD _2. Then, the control unit 190A sends the generated selection designation SLC to the signal processing unit 130A (see FIG. 2).

  Note that the above-mentioned predetermined difference is determined in advance based on experiments, simulations, experience, and the like from the viewpoint of ensuring high-quality audio reproduction and suppressing the change frequency of the signal selected by the selection designation SLC. .

  In the signal processing unit 130A, the selection unit 132 receives the selection designation SLC sent from the control unit 190A. Then, the selection unit 132 sends the signal designated by the selection designation SLC to the detection unit 133 as a signal SLD. (See Figure 2)

  Upon receiving the signal SLD sent from the selection unit 132, the detection unit 133 performs detection processing on the signal SLD to generate a signal CSD. And the detection part 133 sends the produced | generated signal CSD to the stereo demodulation unit 140 as an output signal of signal processing unit 130A (refer FIG. 2).

Upon receiving the signal CSD sent from the signal processing unit 130A, the stereo demodulation unit 140 performs stereo demodulation processing including separation processing on the signal CSD to generate output audio signals AOD _L and AOD _R. Then, the stereo demodulation unit 140 sends the generated output audio signals AOD _L and AOD _R to the sound output units 160 _L and 160 _R. As a result, sounds corresponding to the output audio signals AOD _L and AOD _R are output from the sound output units 160 _L and 160 _{R at} a volume according to the volume designation VLC.

As described above, in the first embodiment, RF processing unit 120 _M is, by performing the frequency conversion of the broadcast signal of reproduction channels received by the antenna 110 _M, to generate a signal IFD _M. Also, RF processing unit 120 _S is, performs frequency conversion of the broadcast signal of reproduction channels received by the antenna 110 _S, and generates a signal IFD _S.

Subsequently, the first reproduction signal generator 131 ₁ performs adaptive filtering processing on the signal IFD _M to generate a signal FLD ₁ with a constant level. The second reproduced signal generating unit 131 ₂ performs adaptive filtering on the signal IFD _S, a signal DFD obtained by the adaptive filtering process, the level of the signal obtained by weighting addition of the signals FLD ₁ constant Generated signal FLD ₂ is generated. Then, the control unit 190A is based on the error ER ₁ reflecting the level difference between the level of the signal FLD ₁ and the reference level, and the error ER ₂ reflecting the level difference between the level of the signal FLD ₂ and the reference level. The control unit 190A controls selection of which of the signal FLD ₁ and the signal FLD ₂ is used as a reproduction signal.

  Therefore, according to the first embodiment, it is possible to improve the signal quality of the signal for reproduction while taking advantage of the characteristics of adaptive filtering processing and synthesis diversity.

In the first embodiment, the level of the signal FLD ₁ generated by the adaptive filtering process in the first reproduction signal generation unit 131 ₁ and the signal generated by the adaptive filtering process in the second reproduction signal generation unit 131 ₂ The level of FLD ₂ is made identical. For this reason, the amount of change in the reproduced sound when the selection of the signal for reproduction is changed is suppressed, and it is possible to prevent the user from feeling uncomfortable.

In the first embodiment, the control unit 190A, the absolute value of the error ER ₁ is, when a small least a predetermined difference than the absolute value of the error ER _2, performs control to select the signal FLD _1. For this reason, the change frequency of the selected signal can be suppressed while ensuring the reproduction of high-quality sound.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference mainly to FIGS.

<Configuration>
FIG. 6 is a block diagram illustrating a schematic configuration of the diversity receiver 100B according to the second embodiment. As shown in FIG. 6, the diversity receiver 100B includes a signal processing unit 130B instead of the signal processing unit 130A, compared to the diversity receiver 100A (see FIG. 1) of the first embodiment described above. And it differs in providing the control unit 190B instead of the control unit 190A. Hereinafter, description will be made mainly focusing on these differences.

As shown in FIG. 7, the signal processing unit 130B is different from the signal processing unit 130A (see FIG. 2) described above in place of the selection unit 132 and the detection unit 133, and the detection units 134 ₁ , 134 ₂ , The difference is that noise level detectors 135 ₁ and 135 ₂ and a selector 136 are provided.

The detector 134 ₁ receives the signal FLD ₁ sent from the first reproduction signal generator 131 ₁ . Then, the detection unit 134 ₁ generates a signal DTD ₁ performs detection processing on the signal FLD _1. The signal DTD ₁ generated in this way is sent to the noise level detector 135 ₁ and the selector 136.

The detector 134 ₂ receives the signal FLD ₂ sent from the second reproduction signal generator 131 ₂ . Then, the detection unit 134 ₂ generates a signal DTD ₂ performs the detection processing on the signal FLD _2. Signal DTD ₂ thus generated is sent to the noise level detection unit 135 ₂ and the selector 136.

The noise level detector 135 ₁ receives the signal DTD ₁ sent from the detector 134 ₁ . Then, the noise level detector 135 ₁ detects the level of a component in a predetermined high frequency band outside the audio band in the signal DTD ₁ . The detection result by the noise level detection unit 135 ₁ is sent to the control unit 190B as the noise level ND ₁ .

Note that it can be said that the noise level ND ₁ reflects the signal quality of the signal DTD ₁ . Here, it can be said that the signal quality of the signal DTD ₁ is higher as the noise level ND ₁ is lower.

The noise level detector 135 ₂ receives the signal DTD ₂ sent from the detector 134 ₂ . The noise level detector 135 ₂ detects the level of a component in a predetermined high frequency band outside the audio band in the signal DTD ₂ . The detection result by the noise level detection unit 135 ₂ is sent to the control unit 190B as the noise level ND ₂ .

It can be said that the noise level ND ₂ reflects the signal quality of the signal DTD ₂ . Here, it can be said that the signal quality of the signal DTD ₂ is higher as the noise level ND ₂ is lower. When the noise level ND ₂ is higher than the noise level ND ₁ becomes since that generated the signals FLD ₂ in consideration of the signal IFD _S, it has become a signal FLD ₁ only the signal quality following signals FLD ₂ obtained in It can be said that.

The selection unit 136 receives the signal DTD ₁ sent from the detection unit 134 ₁ and the signal DTD ₂ sent from the detection unit 134 ₂ . Then, the selection unit 136 selects either the signal DTD ₁ or the signal DTD ₂ according to the selection designation SLC sent from the control unit 190B, and sends the selected signal to the stereo demodulation unit 140 as the signal CSD.

The control unit 190B is different from the control unit 190A described above in that it receives noise levels ND ₁ and ND ₂ instead of the errors ER ₁ and ER ₂ . Then, the control unit 190B generates a selection designation SLC based on the noise levels ND ₁ and ND ₂ and sends the generated selection designation SLC to the signal processing unit 130B. The generation process of the selection designation SLC by the control unit 190B will be described later.

[Operation]
Next, the operation of diversity receiving apparatus 100B configured as described above will be described mainly focusing on signal processing performed by signal processing unit 130B and signal selection control processing performed by control unit 190B.

As a premise, the diversity receiving apparatus 100B has started a broadcast receiving operation, and the control unit 190B sets the reproduction channel to the RF processing units 120 _M and 120 _S according to the channel selection designation input to the input unit 170. It is assumed that As a result, from the RF processing units 120 _M and 120 _S , signals IFD _M and IFD _S corresponding to the reception results of the broadcast waves of the reproduction channel by the antennas 110 _M and 110 _S are sent to the signal processing unit 130B. (See FIG. 6).

Further, it is assumed that the control unit 190B sends the volume designation VLC generated according to the designation of the output volume input to the input unit 170 to the sound output units 160 _L and 160 _R (see FIG. 6).

In such a state, signal processing by the signal processing unit 130B is executed. In such signal processing, the signal processing unit 130B, a first reproduction signal generating unit 131 ₁ receives a signal IFD _M sent from the RF processing unit 120 _M. Subsequently, the first reproduction signal generator 131 ₁ operates in the same manner as in the first embodiment to generate the signal FLD ₁ . Then, the first reproduction signal generator 131 ₁ sends the generated signal FLD ₁ to the second reproduction signal generator 131 ₂ and the detector 134 ₁ (see FIG. 7).

Further, the signal processing unit 130B, the second reproduced signal generating unit 131 ₂ is subjected to signal IFD _S sent from the RF processing unit 120 _S. Further, the second reproduction signal generator 131 ₂ receives the signal FLD ₁ sent from the first reproduction signal generator 131 ₁ . Subsequently, the second reproduction signal generator 131 ₂ operates in the same manner as in the first embodiment to generate the signal FLD ₂ . Then, the second reproduction signal generator 131 ₂ sends the generated signal FLD ₂ to the detector 134 ₂ (see FIG. 7).

Receiving signal FLD ₁ sent from the first reproduction signal generating unit 131 _1, the detection unit 134 ₁ generates a signal DTD ₁ performs detection processing on the signal FLD _1. The detector 134 _{1 then} sends the generated signal DTD ₁ to the noise level detector 135 ₁ and the selector 136 (see FIG. 7).

Receiving signal FLD ₂ sent from the second reproduction signal generating unit 131 _2, the detection unit 134 ₂ generates a signal DTD ₂ performs the detection processing on the signal FLD _2. Then, the detection unit 134 _2, the generated signal DTD _2, sent to the noise level detection unit 135 ₂ and the selector 136 (see FIG. 7).

When receiving the signal DTD ₁ sent from the detector 134 ₁ , the noise level detector 135 ₁ detects the level of a component in a predetermined high frequency band outside the audio band in the signal DTD ₁ . Then, the noise level detection unit 135 ₁ sends the detection result to the control unit 190B as the noise level ND ₁ .

Further, when receiving the signal DTD ₂ sent from the detection unit 134 _2, the noise level detecting unit 135 ₂ detects the level of the components in a predetermined frequency band out of the audio band in the signal DTD _2. Then, the noise level detection unit 135 ₂ sends the detection result as the noise level ND ₂ to the control unit 190B.

Noise level detecting section 135 noise level ND ₁ sent from _1, and receives the noise level ND ₂ sent from the noise-level detection unit 135 _2, the control unit 190B, the noise level ND ₂ is above the noise level ND ₁ Also, it is determined whether the difference is higher than a predetermined level difference. If the result of the determination is affirmative, the control unit 190B generates a selection specification SLC specifying the signal DTD ₁ generated by the detection unit 134 ₁ based on the signal FLD ₁ . Then, the control unit 190B sends the generated selection designation SLC to the signal processing unit 130B (see FIG. 7).

On the other hand, the result of the determination is the case is negative, the control unit 190B generates a selection designated SLC specifying signal DTD ₂ generated by the detection unit 134 ₂ based on the signal FLD _2. Then, the control unit 190B sends the generated selection designation SLC to the signal processing unit 130B (see FIG. 7).

  The predetermined level difference described above is determined in advance based on experiments, simulations, experiences, and the like from the viewpoint of ensuring the reproduction of high-quality audio and suppressing the change frequency of the signal selected by the selection designation SLC. It is done.

  In the signal processing unit 130B, the selection unit 136 receives the selection designation SLC sent from the control unit 190B. Then, the selection unit 136 sends the signal designated by the selection designation SLC to the stereo demodulation unit 140 as the output signal CSD of the signal processing unit 130B (see FIG. 7).

Upon receiving the signal CSD sent from the signal processing unit 130B, the stereo demodulation unit 140 operates in the same manner as in the first embodiment, and generates output audio signals AOD _L and AOD _R. Then, the stereo demodulation unit 140 sends the generated output audio signals AOD _L and AOD _R to the sound output units 160 _L and 160 _R. As a result, sounds corresponding to the output audio signals AOD _L and AOD _R are output from the sound output units 160 _L and 160 _{R at} a volume according to the volume designation VLC.

As described above, in the second embodiment, RF processing unit 120 _M is, by performing the frequency conversion of the broadcast signal of reproduction channels received by the antenna 110 _M, to generate a signal IFD _M. Also, RF processing unit 120 _S is, performs frequency conversion of the broadcast signal of reproduction channels received by the antenna 110 _S, and generates a signal IFD _S.

Subsequently, the first reproduction signal generator 131 ₁ performs adaptive filtering processing on the signal IFD _M to generate a signal FLD ₁ with a constant level. The second reproduced signal generating unit 131 ₂ performs adaptive filtering on the signal IFD _S, a signal DFD obtained by the adaptive filtering process, the level of the signal obtained by weighting addition of the signals FLD ₁ constant Generated signal FLD ₂ is generated.

Next, generation detection unit 134 _1, and generates a signal DTD ₁ performs detection processing on the signal FLD _1, the detection unit 134 _2, a signal DTD ₂ performs the detection processing on the signal FLD ₂ To do. The noise level detector 135 ₁ detects the noise level of the signal DTD ₁ , and the noise level detector 135 ₂ detects the noise level of the signal DTD ₂ .

The noise level ND ₁ is the noise level of the detection result of the signal DTD _1, and, based on the noise level ND ₂ is the noise level of the detection result of the signal DTD _2, control unit 190B is the signal DTD ₁ and signal DTD ₂ , that is, selection of which one of the signal FLD ₁ and the signal FLD ₂ is used as a signal for reproduction is controlled.

  Therefore, according to the second embodiment, it is possible to improve the quality of a reproduction signal while making use of the characteristics of adaptive filtering processing and synthesis diversity.

Further, in the second embodiment, as in the case of the first embodiment, the level of the signal FLD ₁ generated by the adaptive filtering process in the first reproduction signal generation unit 131 ₁ and the second reproduction signal generation unit 131. ₂ is equalized with the level of the signal FLD ₂ generated by the adaptive filtering process in FIG. For this reason, the amount of change in the reproduced sound when the selection of the signal for reproduction is changed is suppressed, and it is possible to prevent the user from feeling uncomfortable.

In the second embodiment, as in the case of the first embodiment, the control unit 190B selects the signal DTD ₁ when the noise level ND ₁ is smaller than the noise level ND ₂ by a predetermined level difference or more ( As a result, control for selecting the signal FLD ₁ is performed. For this reason, the change frequency of the selected signal can be suppressed while ensuring the reproduction of high-quality sound.

[Modification of Embodiment]
The present invention is not limited to the above-described embodiment, and various modifications are possible.

For example, in the first and second embodiments described above, the algorithm disclosed in “2.1” of Non-Patent Document 1 described above is employed when the levels of the signals FLD ₁ and FLD ₂ are fixed. On the other hand, when the levels of the signals FLD ₁ and FLD ₂ are fixed, the algorithm disclosed in “2.2” of Non-Patent Document 1 described above may be employed. Furthermore, other algorithms may be employed.

  In the first and second embodiments, “½” is employed as the constant α. On the other hand, you may employ | adopt the other value obtained by experiment, simulation, etc. as constant (alpha).

In the first and second embodiments, the RF processing unit 120 _S may select a channel different from the reproduction channel during the period in which the signal FLD ₁ is selected for reproduction. In this case, it is possible to automatically search for a receivable broadcasting station while ensuring the reproduction quality of the audio corresponding to the selected reproduction channel.

  In addition, the control unit and the signal processing unit in the above embodiment are configured as a computer as a calculation unit including a CPU (Central Processing Unit), a DSP (Digital Signal Processor), and the like, and a program prepared in advance is executed on the computer. By doing so, you may make it perform the function of the control unit in the above-mentioned embodiment, and a signal processing unit. This program is recorded on a computer-readable recording medium such as a hard disk, CD-ROM, or DVD, and is read from the recording medium and executed by the computer. The program may be acquired in a form recorded on a portable recording medium such as a CD-ROM or DVD, or may be acquired in a form distributed via a network such as the Internet. Also good.

100A, 100B: Diversity receiver 120 _M : RF processing unit (first frequency converter)
120 _S ... RF processing unit (second frequency converter)
131 ₁ ... First reproduction signal generation unit 131 _2. Second reproduction signal generation unit 134 ₁ ... Detection unit (first detection unit)
134 ₂ ... Detection section (second detection section)
135 ₁ ... Noise level detector (first noise level detector)
135 ₂ ... Noise level detector (second noise level detector)
190A, 190B ... Control unit (control unit)

Claims (9)

A first frequency converter that receives the first antenna and performs frequency conversion of the broadcast signal of the selected channel to generate a first frequency converted signal;
A second frequency conversion unit that receives a second antenna different from the first antenna and performs frequency conversion of the broadcast signal of the selected channel to generate a second frequency conversion signal;
A first reproduction signal generation unit that performs a first adaptive filtering process on the first frequency conversion signal and generates a first reproduction signal with a constant level;
Second reproduction in which a second adaptive filtering process is performed on the second frequency conversion signal, and the level of the signal obtained by weighted addition of the signal obtained by the second adaptive filtering process and the first reproduction signal is made constant A second reproduction signal generator for generating a signal for use;
A control unit that controls which of the first reproduction signal and the second reproduction signal is selected based on the signal quality of the first reproduction signal and the signal quality of the second reproduction signal; ;
A diversity receiver characterized by comprising:   The diversity receiving apparatus according to claim 1, wherein the second adaptive filtering process is a process of making the level of the first reproduction signal equal to the level of the second reproduction signal.   The control unit performs control to select the first reproduction signal when the signal quality of the first reproduction signal is higher than the signal quality of the second reproduction signal by a predetermined quality difference or more. The diversity receiver according to claim 1, wherein   The control unit acquires first error information reflecting a difference between a reference level in the first adaptive filtering process and a level of the first reproduction signal as an index of the signal quality of the first reproduction signal. The second error information reflecting the difference between the reference level in the second adaptive filtering process and the level of the second reproduction signal is obtained as an indicator of the signal quality of the second reproduction signal. The diversity receiving device according to any one of claims 1 to 3. A first detector for detecting the first reproduction signal;
A first noise level detector that detects a noise level included in a signal of a detection result by the first detector;
A second detector for detecting the second reproduction signal;
A second noise level detection unit for detecting a noise level included in a signal of a detection result by the second detection unit;
The control unit acquires a detection result by the first noise level detection unit as an index of the signal quality of the first reproduction signal, and the second noise as an index of the signal quality of the second reproduction signal. Get the detection result by the level detector,
The diversity receiver according to any one of claims 1 to 3, wherein The first noise level detection unit detects a level of a component in a frequency range higher than an audio band included in the first reproduction signal;
The second noise level detection unit detects a level of a component in a frequency range higher than the audio band included in the second reproduction signal;
The diversity receiver according to claim 5. A first frequency converter that receives the first antenna and performs frequency conversion of the broadcast signal of the selected channel to generate a first frequency converted signal; and receives the second antenna that is different from the first antenna; A diversity reception method used in a diversity reception device comprising: a second frequency conversion unit that performs frequency conversion of a broadcast signal of the selected channel to generate a second frequency conversion signal;
A first reproduction signal generation step of performing a first adaptive filtering process on the first frequency converted signal to generate a first reproduction signal with a constant level;
Second reproduction in which a second adaptive filtering process is performed on the second frequency conversion signal, and the level of the signal obtained by weighted addition of the signal obtained by the second adaptive filtering process and the first reproduction signal is made constant A second reproduction signal generation step for generating a reproduction signal;
A control step of controlling which of the first reproduction signal and the second reproduction signal is selected based on the signal quality of the first reproduction signal and the signal quality of the second reproduction signal; ;
A diversity receiving method comprising:   A diversity reception program causing a computer included in a diversity reception apparatus to execute the diversity reception method according to claim 7.   9. A recording medium on which the diversity reception program according to claim 8 is recorded so as to be readable by a computer included in the diversity reception apparatus.

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