JP6898558B2 - Signal processing equipment, signal processing methods, and wireless devices - Google Patents

Description

The present invention relates to a signal processing device that performs amplitude control processing and band limiting processing on an input signal, a signal processing method, and a wireless device including the signal processing device.

Generally, in a wireless transmitter, compression processing is performed in order to suppress fluctuations in the level of a transmission signal. The compression process is often performed by amplifying and limiting the input signal and removing the resulting harmonic components with a low-pass filter.

However, if the band limiting process is performed after the limiting process (amplitude limiting process), the amplitude after the band limiting process may be larger than the amplitude limited by the amplitude limiting process due to the influence of the phase change or the like. Therefore, in the amplitude limiting process, it is necessary to limit the amplitude larger than the originally required limit. Further, when the signal removed by the band limiting process is large, the amplitude after the band limiting process is significantly smaller than the amplitude limited by the amplitude limiting process.

Further, when the amplitude limiting process is performed, an unnecessary signal is generated outside the band due to distortion, so that the band limiting process is indispensable after the amplitude limiting process. However, there arises a problem that the amplitude is changed again by this band limiting process.

In this way, the band limiting process changes the amplitude, and the band limiting process affects the band (unnecessary signals are generated). Therefore, it is difficult to make the band limiting process and the amplitude limiting process compatible with each other. ..

Therefore, for example, Patent Document 1 describes a transmission peak limiting circuit that estimates the influence of the band limiting process by the filter on the amplitude, sets the amplitude limit value according to the estimation result, and performs the amplitude limiting process. ..

Further, in Patent Document 2, the absolute value of the digital input data before that including the latest input digital input data is stored while being constantly updated for a preset number of samples, and the latest digital input is obtained. Each time data is input, the maximum value of the accumulated digital input data of a predetermined number of samples is detected, and the latest digital input data or the previous digital input data by a predetermined number of samples is divided by the maximum value. A compression processing device that realizes compression processing by outputting data is described.

Further, conventionally, there has been a configuration in which an unnecessary signal is gradually eliminated and a desired output signal is obtained by repeating an amplitude limiting process and a band limiting process on an input signal. For example, as shown in FIG. 5, the amplitude limiting unit 210 that limits the amplitude by multiplying the amplitude of the input signal by a gain, calculates the “gain control value” for measuring the amplitude of the input signal and controlling the gain. In the signal processing device 200 provided with the amplitude measuring unit 220 and the band limiting unit 230 for band limiting the signal after the amplitude limitation, the amplitude limiting processing in the amplitude limiting unit 210 and the band limiting processing in the band limiting unit 230 are repeated. As a result, there was a configuration in which a desired signal was obtained.

Japanese Unexamined Patent Publication No. 2003-152593 (published on May 23, 2003) Japanese Unexamined Patent Publication No. 2000-165253 (published on June 16, 2000)

However, the above-mentioned prior art has the following problems. In the technique described in Patent Document 1, the influence of the band limiting process by the filter on the amplitude is estimated and the amplitude limiting value is set. However, since it is only an estimated value, the result of performing band limiting processing on the signal after amplitude limitation may not always be a desired value.

Further, in the technique described in Patent Document 2, when the band limitation is steep, overshoot occurs when the band limitation processing is performed on the signal subjected to the amplitude limitation processing. Furthermore, it is difficult to deal with a signal such as a pulse whose amplitude changes suddenly.

Further, the conventional configuration in which the amplitude limiting process and the band limiting process are repeated has a problem that the processing time increases according to the number of repetitions.

One aspect of the present invention has been made in view of the above problems, and an object of the present invention is to realize a signal processing device or the like that appropriately performs both amplitude control processing and band limitation processing with a simple configuration. It is in.

In order to solve the above problems, the signal processing apparatus according to one aspect of the present invention includes a first band limiting unit that limits the band of the input input signal, and a band limiting process by the first band limiting unit. The measurement unit that measures the amplitude of the input signal after that, the amplitude control unit that controls the amplitude of the input signal based on the predetermined amplitude of the output signal and the measured amplitude, and the band limitation. It has the same characteristics as the first band limiting unit, and is characterized by including a second band limiting unit that limits the bandwidth of the input signal subjected to the amplitude control processing by the amplitude control unit. There is.

According to the above configuration, the band limiting process of the input signal is performed by the second band limiting section that performs the band limiting process after the amplitude control process and the first band limiting section having the same characteristics regarding the band limiting, and the band limiting process is performed. Measure the amplitude of the subsequent input signal. Then, the amplitude control process is performed based on the amplitude of the output signal determined in advance and the measured amplitude, and then the band limiting process is performed by the second band limiting unit. As a result, the amplitude control processing can be performed in consideration of the influence on the amplitude that occurs when the band limiting processing by the second band limiting unit is performed. Therefore, with a simple configuration, it is possible to appropriately perform both the amplitude control process and the band limitation process on the input signal.

In the signal processing device, the amplitude control unit has a configuration in which amplitude control is performed by multiplying the amplitude of the input signal by a value obtained by dividing the amplitude of the predetermined output signal by the amplitude measured by the measurement unit. You may.

According to the above configuration, the amplitude can be controlled in consideration of the influence of the band limiting process on the amplitude in advance. Therefore, it is possible to appropriately perform both the amplitude control process and the band control process on the input signal.

The signal processing device is configured to include a delay unit that delays the input signal by the time that the input signal is processed by the first band limiting unit and the measuring unit and inputs the input signal to the amplitude control unit. There may be.

According to the above configuration, the input signal input to the amplitude control unit is delayed by the time processed by the first band limiting unit and the measuring unit. As a result, the timing at which the input signal is input to the amplitude control unit can be the same as the timing at which the amplitude control unit acquires the change in amplitude. Therefore, the amplitude can be appropriately controlled with respect to the input signal without causing a deviation in the signal to be amplitude-controlled.

In order to solve the above problems, the wireless device according to one aspect of the present invention is characterized by including the above signal processing device. As a result, the same effect as the above-mentioned effect is obtained.

In order to solve the above problems, the signal processing method according to one aspect of the present invention is a signal processing method for processing an input signal, and is a first band limitation that limits the band of the input input signal. The input signal is based on the step, the measurement step of measuring the amplitude of the input signal after the band limitation processing by the first band limitation step, and the predetermined output signal amplitude and the measured amplitude. A second band that limits the band to the input signal that has been subjected to the amplitude control processing in the amplitude control step with the same characteristics as the band limitation in the amplitude control step that controls the amplitude and the band limitation in the first band limitation step. It is characterized by including limiting steps.

According to the above method, the same effect as the above-mentioned effect is obtained.

The signal processing device according to each aspect of the present invention may be realized by a computer. In this case, the signal processing device is made into a computer by operating the computer as each part (software element) included in the signal processing device. The control program of the signal processing device to be realized and the computer-readable recording medium on which the control program is recorded also fall within the scope of the present invention.

According to one aspect of the present invention, the amplitude control process can be performed in consideration of the influence of the band limitation process executed on the input signal on the amplitude in advance. Therefore, the amplitude control process and the band limitation can be performed with a simple configuration. It has the effect of being able to achieve both treatments and apply them appropriately.

It is a functional block diagram which shows the outline of the signal processing apparatus which concerns on one Embodiment of this invention. It is a functional block diagram which shows the outline of the wireless device including the said signal processing apparatus. It is a flowchart which shows the flow of processing in the said signal processing apparatus. It is a functional block diagram which shows the outline of the signal processing apparatus which concerns on the modification. It is a functional block diagram which shows one configuration example of the prior art.

[Embodiment]
Hereinafter, one embodiment of the present invention will be described in detail. First, the wireless device 100 according to the present embodiment will be described with reference to FIG. FIG. 2 is a functional block diagram showing an outline of the wireless device 100. Note that, in FIG. 2, among the functions of the wireless device 100, functions not directly related to the present invention (modulation unit, demodulation unit, mixing unit, local oscillator, amplification unit, etc.) are not shown.

As shown in FIG. 2, the wireless device 100 includes a signal processing device 10, a transmission / reception unit 20, an input / output unit 30, and an antenna 40.

The signal processing device 10 processes the signal input from the input / output unit 30, and outputs the processed signal to the transmission / reception unit 20. Further, the signal processing device 10 processes the signal input from the transmission / reception unit 20 and outputs the processed signal to the input / output unit 30. The details of the signal processing device 10 will be described later.

The transmission / reception unit 20 transmits the signal input from the signal processing device 10 to the outside via the antenna 40. Further, the transmission / reception unit 20 outputs a signal received from the outside via the antenna 40 to the signal processing device 10.

The input / output unit 30 receives a signal input to the wireless device 100. Further, the input / output unit 30 outputs a signal from the wireless device 100 to the outside. The input / output unit 30 is, for example, a microphone and a speaker. When the input / output unit 30 is a microphone, the input / output unit 30 converts the sound received from the user or the like into a digital signal by A / D conversion (not shown) and outputs it to the signal processing device 10. When the input / output unit 30 is a speaker, the input / output unit 30 converts the signal output by the signal processing device 10 into voice by D / A conversion (not shown) and outputs the signal to the outside. The input / output unit 30 may include a display device that displays various information in the wireless device 100. Further, the signal transmitted and received by the wireless device 100 is not limited to voice. The wireless device 100 may send and receive data other than voice such as characters and image data.

The antenna 40 emits (transmits) a signal output from the transmission / reception unit 20 into space as a radio wave, and receives the radio wave in the space and outputs it to the transmission / reception unit 20.

With the above configuration, the voice input to the wireless device 100 is input to the signal processing device 10 from the input / output unit 30, signal processing is performed by the signal processing device 10, and the radio wave is transmitted from the antenna 40 via the transmission / reception unit 20. Is fired (transmitted) into space.

Further, the radio waves of the voice emitted (transmitted) from the external wireless device are input from the antenna 40 to the signal processing device 10 via the transmission / reception unit 20, signal processing is performed by the signal processing device 10, and the input / output unit. It is output as audio from 30.

In the present embodiment, the wireless device 100 is described as a wireless device having both a transmission / reception function, but may be a wireless device having only a transmission function or a wireless device having only a reception function. You may. Further, the wireless device 100 may be a fixed device or a mobile device.

[Configuration of signal processing device]
Next, the signal processing device 10 will be described with reference to FIG. FIG. 1 is a functional block diagram showing an outline of the signal processing device 10. As shown in FIG. 1, the signal processing device 10 according to the present embodiment includes a band limiting unit 11, an amplitude measuring unit 12, an amplitude control unit 13, and a band limiting unit 14.

The band limiting unit 11 performs band limiting processing on the input signal input to the signal processing device 10, and outputs the signal after the band limiting processing to the amplitude measuring unit 12. Similarly, the band limiting unit 14 performs band limiting processing on the signal output by the amplitude control unit 13, and outputs the signal after the band limiting processing as an output signal. The band limiting unit 11 and the band limiting unit 14 have the same characteristics regarding the band limiting and operate independently. Typical examples of the band limiting unit 11 and the band limiting unit 14 are band limiting filters such as a low pass filter (LPF) and a band pass filter (BPF).

The amplitude measuring unit 12 measures the amplitude of the signal after the band limiting processing by the band limiting unit 11. Then, the amplitude measurement unit 12 calculates a value (hereinafter, referred to as a “gain control value”) used for controlling the gain in the amplitude control process by the amplitude control unit 13. Then, the amplitude measurement unit 12 outputs the calculated gain control value to the amplitude control unit 13.

The gain control value is determined so that the amplitude of the signal processed by the band limiting unit 14 becomes a predetermined output signal amplitude (that is, a desired output level). Specifically, when the amplitude of the input signal is X, the amplitude of the signal processed by the band limiting unit 11 is L, and the amplitude of the predetermined output signal is Y, the amplitude measuring unit 12 sets the gain control value. Calculate Y / L. As a result, when a signal having an amplitude X is input to the signal processing device 10, the amplitude of the input signal is multiplied by "Y / L" by the amplitude control unit 13 and "L / X" by the band limiting unit 14. .. Therefore, X × “Y / L” × “L / X” = Y, and the amplitude of the output signal can be set to a predetermined Y.

With the above configuration, as a result of the band limiting process by the band limiting unit 14, the amplitude of the output signal becomes "L / X" times the amplitude of the signal output by the amplitude control unit 13, but the amplitude control unit 13 " Since "Y / L" is multiplied, the amplitude of the output signal is X × (Y / L) × (L / X) = Y. As a result, the output signal can have a desired amplitude without being restricted by the band limitation unit 14.

As described above, according to the present embodiment, the amplitude control processing can be performed in consideration of the influence of the band limitation processing on the amplitude in advance. Therefore, it is possible to appropriately perform both the amplitude control process and the band limitation process on the input signal.

As described above, the signal processing device 10 according to the present embodiment is after the band limiting unit 11 (first band limiting unit) that limits the band of the input signal and the band limiting process by the band limiting unit 11. The amplitude measuring unit 12 (measurement unit) for measuring the amplitude of the input signal, and the amplitude control unit 13 for controlling the amplitude of the input signal based on the predetermined output signal amplitude and the measured amplitude. The band limiting unit 14 (second band limiting unit) which has the same characteristics related to the band limiting as the band limiting unit 11 and performs band limiting on the input signal subjected to the amplitude control processing by the amplitude control unit 13. ) And.

In this way, the signal processing device 10 performs the band limiting process of the input signal by the band limiting unit 11 having the same characteristics as the band limiting unit 14 that limits the band after the amplitude control, and uses the result to obtain the gain in the amplitude control process. Is in control. As a result, the amplitude can be controlled in consideration of the influence of the band limiting process executed on the input signal on the amplitude in advance. Therefore, the amplitude control process and the band limiting process are appropriately performed on the input signal at the same time. be able to.

Further, since the signal processing device 10 has a configuration in which the influence of the band limiting process on the amplitude is taken into consideration in advance, even if the characteristic is such that the amplitude changes significantly due to the band limiting process, the amplitude is appropriately adjusted in the amplitude control process. Can be controlled.

Further, since the signal processing device 10 is not configured to perform the amplitude control processing after the band limiting processing, no unnecessary signal is generated outside the band.

Further, since the signal processing device 10 is not configured to repeat the band limiting process and the amplitude control process a plurality of times, there is no problem that the processing time is increased as in the prior art.

Further, since the signal processing device 10 is configured to perform a series of processing by the band limiting unit 11, the amplitude measuring unit 12, the amplitude control unit 13, and the band limiting unit 14 each time an input signal is input, the input signal is input. Even if the amplitude of the input signal changes suddenly (for example, even if the input signal contains pulses), the amplitude control process and the amplitude control process are performed after calculating an appropriate gain limit value according to the change in the amplitude of the input signal. Band limitation processing can be performed.

Further, since it is desirable to control the gain by the amplitude control processing for the signal that is not the target of the band limiting processing (that is, the signal that passes through the band limiting filter), the band limiting unit 11 in the signal processing device 10 The amplitude is measured for the signal after the band limitation processing by, and the gain limit value is calculated. In a configuration in which amplitude measurement is performed on a signal before band limiting processing as in the prior art, when a signal having a large amplitude is mixed in the input signal, the signal is removed by band limiting processing (noise, etc.). Even so, there is a problem that the gain is lowered in order to uniformly lower the amplitude of the input signal, and even the amplitude of the signal passing through the band limiting filter becomes smaller than necessary. Such a problem does not occur in the signal processing device 10.

The signal processing device 10 performs amplitude control processing on the signal passing through the band limiting filter even when the amplitude of the signal removed by the band limiting processing is small. In other words, in the band limiting process by the band limiting unit 14 after the amplitude limiting process, only the signals not related to the amplitude control process are removed.

[Processing flow in signal processing equipment]
Next, the flow of processing in the signal processing device 10 will be described with reference to FIG. FIG. 3 is a flowchart showing a processing flow in the signal processing device 10.

As shown in FIG. 3, first, an input signal is input to the signal processing device 10 (S101). Next, the signal processing device 10 executes band limiting processing on the input signal by the band limiting unit 11 (S102, first band limiting step). Then, the signal processing device 10 measures the amplitude of the band-limited signal by the amplitude measuring unit 12, and calculates the gain control value using the predetermined output signal amplitude and the measured amplitude (the measured amplitude). S103, measurement step).

Next, the signal processing device 10 executes an amplitude control process on the input signal by the amplitude control unit 13 using the gain control value calculated in step S103 (S104, amplitude control step). Finally, the signal processing device 10 executes band limiting processing by the band limiting unit 14 on the signal subjected to the amplitude control processing (S105, second band limiting step), and outputs the signal after the band limiting processing (S105, second band limiting step). S106).

By sequentially executing steps S101 to S106 described above each time an input signal is input, the signal processing device 10 appropriately performs amplitude control processing and band limiting processing on the entire input signal. Output the output signal.

[Modification example]
A modified example of the signal processing device 10 will be described below with reference to FIG. FIG. 4 is a functional block diagram showing an outline of the signal processing device 10a according to the present modification.

In the signal processing device 10a, in addition to the configuration of the signal processing device 10, a delay unit 15 is provided in front of the amplitude control unit 13. The delay unit 15 delays the input signal by the time that the input signal is processed by the band limiting unit 11 and the amplitude measuring unit 12, and causes the amplitude control unit 13 to input the input signal.

As a result, the processing in the amplitude measurement unit 12 is completed, and the timing at which the gain control value is input from the amplitude measurement unit 12 to the amplitude control unit 13 and the timing at which the input signal is input to the amplitude control unit 13 can be synchronized. it can.

That is, according to the configuration of this modification, the input signal input to the amplitude control unit is only the time processed by the band limiting unit 11 (first band limiting unit) and the amplitude measuring unit 12 (measuring unit). It will be delayed. As a result, the timing at which the input signal is input to the amplitude control unit 13 and the timing at which the amplitude control unit 13 acquires the gain control value can be the same. Therefore, the amplitude control unit 13 can appropriately perform amplitude control with respect to the input signal without causing a deviation in the signal to be amplitude-controlled.

[Example of realization by software]
The control block (particularly the band limiting unit 11, the amplitude measuring unit 12, the amplitude control unit 13, the band limiting unit 14, and the delay unit 15) of the signal processing device 10 (10a) is formed in an integrated circuit (IC chip) or the like. It may be realized by a logic circuit (hardware) or by software.

In the latter case, the signal processing device 10 (10a) includes a computer that executes instructions of a program that is software that realizes each function. The computer includes, for example, one or more processors and a computer-readable recording medium that stores the program. Then, in the computer, the processor reads the program from the recording medium and executes it, thereby achieving the object of the present invention. As the processor, for example, a DSP (digital signal processor) or a CPU (Central Processing Unit) can be used. As the recording medium, a "non-temporary tangible medium", for example, a ROM (Read Only Memory) or the like, a tape, a disk, a card, a semiconductor memory, a programmable logic circuit, or the like can be used. Further, a RAM (Random Access Memory) for expanding the above program may be further provided. Further, the program may be supplied to the computer via an arbitrary transmission medium (communication network, broadcast wave, etc.) capable of transmitting the program. It should be noted that one aspect of the present invention can also be realized in the form of a data signal embedded in a carrier wave, in which the above program is embodied by electronic transmission.

The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and the embodiments obtained by appropriately combining the technical means disclosed in the different embodiments. Is also included in the technical scope of the present invention.

10, 10a Signal processing device 11 Band limiting section (first band limiting section)
12 Amplitude measurement unit (measurement unit)
13 Amplitude control unit 14 Band limiting unit (second band limiting unit)
15 Delay 100 Wireless device

Claims (5)

A first band limiting unit that limits the band of the input signal,
A measuring unit that measures the amplitude of the input signal after the band limiting processing by the first band limiting unit, and a measuring unit.
An amplitude control unit that controls the amplitude of the input signal based on the predetermined amplitude of the output signal and the measured amplitude.
A second band limiting unit that has the same characteristics of limiting the same band as the first band limiting unit and that limits the band to the input signal that has been subjected to amplitude control processing by the amplitude control unit. A signal processing device characterized by being equipped with. The first aspect of claim 1 is characterized in that the amplitude control unit performs amplitude control by multiplying the amplitude of the input signal by a value obtained by dividing the amplitude of the predetermined output signal by the amplitude measured by the measurement unit. The signal processing device described. Claim 1 is characterized in that the input signal is provided with a delay unit for delaying the input signal by the time processed by the first band limiting unit and the measuring unit and inputting the input signal to the amplitude control unit. Or the signal processing apparatus according to 2. A wireless device provided with the signal processing device according to any one of claims 1 to 3. It is a signal processing method that processes the input signal.
The first band limiting step that limits the band of the input signal, and
A measurement step for measuring the amplitude of the input signal after the band limiting process by the first band limiting step, and a measurement step.
An amplitude control step for controlling the amplitude of the input signal based on a predetermined output signal amplitude and the measured amplitude, and an amplitude control step.
A second band limiting step that limits the band to the input signal subjected to the amplitude control processing in the amplitude control step with the same characteristics that limit the same band as the band limiting in the first band limiting step. A signal processing method comprising.

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