JP2006101102A - Radio equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide multi-mode radio equipment in which characteristics of filtering for reception band limitation is easily changed. <P>SOLUTION: An analog-digital converting means 21 converts a received signal from an analog signal to a digital signal, detecting means 22, 23, 24a, and 24b detect the received signal converted into the digital signal, and a digital signal processing means 27 performs, through digital signal processing, filtering processing for limiting the band of the signal to limit the band of the signal as the detection result, and demodulates the signal through digital signal processing; and filtering characteristic determining data supplying means 6, 52, and 28 supply data determining filtering characteristics to the digital signal processing means 27, which performs the filtering processing for filtering characteristics determined by the supplied data. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a multimode radio, and more particularly, to a radio capable of performing reception band limitation by digital signal processing and easily changing characteristics of filtering for performing the reception band limitation.

For example, study of a software defined radio that can change the basic functions of wireless such as bandwidth and modulation / demodulation by software on a processor such as a DSP (Digital Signal Processor) or a CPU (Central Processing Unit). Is underway.
FIG. 4 shows a configuration example related to the reception function of the multimode radio.
The multimode wireless device of this example includes an antenna 61 for receiving radio waves, a high frequency unit 62, a signal processing unit 63, an interface unit 64, a control unit 65, and an operation terminal 66.

The high frequency unit 62 includes a receiving unit 71, two switches 72 and 74, a plurality of band limiting filters 73 a, 73 b,.
The signal processing unit 63 includes an A / D (Analog / Digital) converter 81, an oscillator (oscillator) 82, a phase shifter 83, two multipliers 84a and 84b, and two low-frequency limiting filters 85a. , 85b, two down converters 86a, 86b, a DSP 87, and a CPU 88.
The interface unit 64 includes an audio D / A (Digital / Analog) converter 91 and a CPU 92.
The control unit 65 includes a wireless control unit 101 and a CPU 102.

Here, the high-frequency unit 62 is provided with a plurality of band limiting filters 73a, 73b,..., 73c having different transfer characteristics. The switch 74 on the side is switched, and any one band limiting filter is selected and used for band limiting.
In the signal processing unit 63, the DSP 87 performs demodulation processing by numerical calculation.

  However, in the multimode radio as shown in FIG. 4, various types of band limiting filters 73a, 73b,..., 73c of the high-frequency unit 62 are required for each modulation method. Various band limiting filters are required. For this reason, it is difficult to prepare filters corresponding to all methods in terms of the mounting area of the high-frequency unit 62 and the like. Moreover, in order to correspond to a new band, it is necessary to replace with another high frequency unit 62.

JP 2003-174394 A

As described above, in the wireless device as shown in FIG. 4, the band limiting process is realized by the hardware (H / W) of the high frequency unit 62, and the characteristics of filtering for limiting the reception band are easily changed. There was a problem that it was not possible.
In the software defined radio, the band limiting process is performed by a numerical operation on the DSP, and a filter bank having a plurality of bandwidths and which one of the filter banks to select from the CPU is selected from the CPU. It is possible to cope with various bandwidths by the changeover switch determined by the instruction. However, in such a configuration, in order to cope with the new bandwidth, it is necessary to change the configuration of the filter bank inside the DSP program, and accordingly, the DSP program needs to be recompiled.

  The present invention has been made in view of the above-described conventional circumstances, and provides a radio device that can limit the reception band by digital signal processing and easily change the filtering characteristics for performing the reception band limitation. For the purpose.

In order to achieve the above object, the radio apparatus according to the present invention processes a received signal with the following configuration.
That is, the analog-digital conversion means converts the received signal from an analog signal to a digital signal. The detection means detects the reception signal converted into a digital signal by the analog-digital conversion means. The digital signal processing means performs filtering processing for limiting the band of the signal by digital signal processing, band-limits the signal of the detection result by the detection means, and demodulates the signal after the band limitation by digital signal processing.
The filtering characteristic determination data supply means supplies data for determining the filtering characteristic of the filtering process to the digital signal processing means. The digital signal processing means executes a filtering process of a filtering characteristic determined by data supplied from the filtering characteristic determination data supply means by digital signal processing.

  Accordingly, the filtering process for band limiting the received signal is performed by digital signal processing, and the filtering characteristics of the filtering process are determined by the supplied data. For example, when receiving band limiting is performed by digital signal processing, It is possible to easily change the characteristics of filtering for band limitation.

Here, various signals may be used as the received signal.
Various processes may be used as the received signal processing.
Various modes may be used as the detection mode. For example, a mode in which quadrature detection is performed on a quadrature-modulated reception signal can be used.
In addition, various modes may be used as a mode of demodulation. For example, a mode in which a received signal modulated by a predetermined modulation method is demodulated by a method corresponding to the modulation method can be used. .
The digital signal processing means can be configured using a DSP, for example.
Further, the filtering characteristic determination data supply means can be configured using, for example, a CPU.

Various characteristics may be used as the filtering characteristics of the filtering process for band limiting the received signal.
Various data may be used as the data for determining the filtering characteristic of the filtering process for band limiting the received signal. For example, the data of the filter coefficient that determines the filtering characteristic is used as the parameter data. It can be used, or data specifying the value of the filter coefficient that determines the filtering characteristics can be used.
Various modes may be used for supplying data for determining the filtering characteristics of the filtering process for band limiting the received signal. For example, a user or the like from among a plurality of preset data A mode of supplying data designated by the user or a mode of supplying data input by a user or the like can be used.

  As described above, according to the radio apparatus of the present invention, the received signal is converted from an analog signal to a digital signal, the received signal converted into the digital signal is detected, and the filtering process for limiting the signal band is performed by the digital signal processing. When the signal of the detection result is band-limited and the signal after the band limitation is demodulated by digital signal processing, data for determining the filtering characteristics of the filtering processing is supplied and determined by the data Since the filtering process of the filtering characteristic is executed by the digital signal process, for example, when the reception band is limited by the digital signal process, the filtering characteristic for performing the reception band limitation can be easily changed.

An embodiment according to the present invention will be described with reference to the drawings.
FIG. 1 shows a configuration example related to the reception function of a multimode radio according to an embodiment of the present invention.
The multimode radio of this example is configured as a software radio, and includes an antenna 1 for receiving radio waves, a high frequency unit 2, a signal processing unit 3, an interface unit 4, a control unit 5, and an operation. A terminal 6 is provided.

The high frequency unit 2 includes a receiving unit 11 and a CPU 12.
The signal processing unit 3 includes an A / D converter 21, an oscillator (oscillator) 22, a phase shifter 23, two multipliers 24a and 24b, two low-frequency limiting filters 25a and 25b, 2 The down converters 26a and 26b, the DSP 27, and the CPU 28 are included.
The DSP 27 realizes the functions of the two band limiting filters 31a and 31b and the function of the demodulator 32 by digital signal processing.
Note that the two received signal processing systems in the signal processing unit 3 correspond to an I component and a Q component, respectively.
The interface unit 4 includes an audio D / A converter 41 and a CPU 42.
The control unit 5 includes a wireless control unit 51 and a CPU 52.

An example of the operation performed by the multi-mode wireless device of this example is shown.
The antenna 1 receives a signal (radio wave) transmitted wirelessly from a transmission-side device, and outputs the received signal to the receiving unit 2.
The receiving unit 11 converts a radio frequency (RF: Radio Frequency) band received signal input from the antenna 1 into a received signal of an intermediate frequency (IF) band by frequency conversion and converts the received signal to an A / D converter 21. Output.
The A / D converter 21 converts the reception signal input from the reception unit 11 from an analog signal to a digital signal and outputs the converted signal to the two multipliers 24a and 24b.
In the signal processing unit 3, digital signal processing is performed on the received signal thereafter.

In this example, quadrature detection processing is performed on the reception signal that is orthogonally modulated on the transmission side, the I component is extracted and processed by the reception signal processing system on the side of one multiplier 24a, and the other multiplier 24b is processed. It is assumed that the Q component is extracted and processed by the reception signal processing system on the other side.
The oscillator 22 oscillates a signal having a predetermined carrier frequency and outputs the signal to the I component multiplier 24 a and the phase shifter 23.
The phase shifter 23 delays the phase of the signal input from the oscillator 22 by 90 degrees and outputs the delayed signal to the Q component multiplier 24b.

The I component multiplier 24a multiplies the reception signal input from the A / D converter 21 and the signal input from the oscillator 22, and outputs the multiplication result to the I component low-frequency limiting filter 25a. .
The Q-component multiplier 24b multiplies the reception signal input from the A / D converter 21 and the signal input from the phase shifter 23, and the multiplication result is supplied to the Q-component low-frequency limiting filter 25b. Output.
In this example, quadrature detection processing is performed by the oscillator 22, the phase shifter 23, and the two multipliers 24a and 24b.

The low-frequency limiting filter 25a for I component cuts (removes) high-frequency components from signals input from the multiplier 24a for I components constituting the quadrature detector, and outputs the signal after the cut. It outputs to the down converter 26a for I components.
The low-frequency limiting filter 25b for the Q component cuts (removes) the high-frequency component from the signals input from the multiplier 24b for the Q component constituting the quadrature detector, and outputs the signal after the cut. Output to the Q component down converter 26b.
In this example, if the same frequency as the intermediate frequency is selected as the frequency of the signal oscillated by the oscillator 22 constituting the quadrature detector, and the high frequency component is cut by the low frequency limiting filters 25a and 25b, the signal is received at the subsequent stage of the quadrature detector. The signal becomes a baseband signal.

The I-component down-converter 26a converts the sampling frequency of the I-component received signal input from the I-component low-frequency limiting filter 25a to a sampling frequency that can be processed by the DSP 27, and the converted signal. Is output to the DSP 27.
The Q-component down converter 26b converts the sampling frequency of the Q-component received signal input from the low-frequency limiting filter 25b for the Q component to a sampling frequency that can be processed by the DSP 27, and the converted signal. Is output to the DSP 27.

The DSP 27 realizes the function of the band limiting filter 31a for the I component by numerical calculation, and performs band limiting processing on the received signal of the I component input from the down converter 26a for I component by digital signal processing.
Similarly, the DSP 27 realizes the function of the band limiting filter 31b for the Q component by numerical calculation, and performs band limiting processing on the received signal of the Q component input from the down converter 26b for Q component by digital signal processing. .
Further, in the DSP 27, the function of the demodulator 32 is realized by numerical calculation, and the received signal of the I component band-limited by the function of the band limit filter 31a for I component and the function of the band limit filter 31b for Q component. Demodulation processing is performed by digital signal processing on the band-limited Q component received signal, and the demodulation result signal is output to the audio D / A converter 41.

The audio D / A converter 41 outputs demodulated sound from the speaker with respect to the signal input from the DSP 27.
The wireless control unit 51 transmits the contents set by the operation terminal 6 to each processing unit such as the high-frequency unit 2, the signal processing unit 3, and the interface unit 4, and manages the status (status) of each processing unit. Is performed via each of these processing units and the CPUs 12, 28, 42, and 52 provided in itself. In this example, the CPUs 12, 28, 42, and 52 can communicate with each other.
The operation terminal 6 is a man-machine interface that realizes various settings related to the wireless device by the user, and transmits the content set by the user to the wireless control unit 51.

Next, the operation performed by the DSP 27 of this example will be described in detail.
The operation and function of the DSP 27 can be switched to an arbitrary modulation / demodulation method that can be used as a multimode radio. For example, the method is changed with reference to control parameters communicated between the CPU 28 and the DSP 27. Alternatively, the method can be changed by software by rewriting the program. As the change of the system, for example, amplitude modulation (AM), frequency modulation (FM), single sideband modulation (SSB), and the like can be switched.

In this example, the bandwidth limiting process is performed using the software of the DSP 27.
Specifically, the DSP 27 implements an FIR type digital filter as the band limiting filters 31a and 31b. The FIR type digital filter is realized by a product-sum operation of current and past input signals and a filter coefficient sequence, and the characteristics (transfer characteristics and cutoff characteristics) of this filter can be switched by changing the filter coefficients.
Therefore, in this example, this filter coefficient is used as a control parameter passed from the CPU 28 to the DSP 27.

FIG. 2 shows an example of a list of control parameters passed from the CPU 28 to the DSP 27.
For example, AM, FM, and SSB can be switched in the control parameter related to the modulation scheme, transmission and reception can be switched in the control parameter related to transmission / reception switching, and whether or not the filter is switched in the control parameter related to the filter switching flag. (For example, “1” value when present, “0” value when absent) can be switched, and the control parameter related to the number of filter taps switches the number TAP related to the number of filter taps. The filter parameters h (0), h (1),..., H (TAP) can be switched in the control parameter related to the filter coefficient.

In this example, filter coefficient data is designated by the user or the like on the operation terminal 6 or the like, and the designated content is received by the CPU 28 of the signal processing unit 3 via the CPU 52 of the control unit 5 or the like, and the signal processing unit 3 The CPU 28 sets filter coefficient data corresponding to the designated contents as a control parameter to the DSP 27.
Here, the filter coefficient data may be input from the operation terminal 6, for example, or the filter coefficient data of a plurality of patterns is stored in advance in the CPU 52 of the control unit 5, the CPU 28 of the signal processing unit 3, or the like. Thus, an aspect may be used in which the filter coefficient data of the pattern designated by the information for identifying the pattern (for example, the pattern number) is read out and set in the DSP 27.

In this example, the selected one is selected from the filter coefficient data (filter coefficient data (1), filter coefficient data (2),...) Of a plurality of patterns managed by the CPU. The filtered filter coefficient data is used as a control parameter.
Here, the filter coefficient data of each pattern is configured as a set of a predetermined number of components (filter coefficients) h (0), h (1),..., H (TAP) determined by the number of filter taps TAP. Is done.

FIG. 3 shows an example of the procedure of processing performed by the DSP 27 of this example.
In the DSP 27, execution of a predetermined program is started, for example, every sampling period.
In this program, first, a control parameter is read (read) from the CPU 28, and an operation and a function to be realized are determined according to the read control parameter (step S1).
At this time, if there is a filter switching command from the operation terminal 6, the CPU 28 selects a filter coefficient sequence corresponding to the command, updates the value of the control parameter, and sets the filter switching flag to a “1” value. To do.

  The DSP 27 checks the state of the filter switching flag among the control parameters received from the CPU 28, and determines whether or not the filter is switched (step S2). As a result, if the filter switching flag has a value of “0”, modulation processing and demodulation processing are executed assuming that there is no filter switching (step S3). On the other hand, when the filter coefficient flag is “1” value, it is assumed that the filter is switched, and after clearing (initializing) the values for the filter coefficient calculation variable and buffer (step S4). , The variables h (0), h (1),..., H (TAP) for the filter coefficient are updated with reference to the control parameters.

In this manner, in the multimode wireless device of this example, the DSP 27 can switch the filter characteristics.
Further, in this example, it is possible to add or expand only the filter coefficient string by the operation terminal 6, which makes it possible to add filtering characteristics flexibly without changing the program of the DSP 27, for example. It is.

As described above, in the multimode wireless device of this example, it is possible to switch between a plurality of modes, and in a configuration capable of realizing various functions and methods, the reception band limiting process is performed by the digital signal processing of the DSP 27. By doing this, the filtering characteristics can be changed flexibly.
Specifically, the multimode radio of this example includes a high-frequency unit 2 that performs frequency conversion, a signal processing unit 3 that performs quadrature detection, downsampling, band limitation, and demodulation processing by digital processing after A / D conversion, An interface unit 4 having a function of D / A converting the demodulated signal and outputting it to an external speaker; a control unit 5 for setting the setting from the operation terminal 6 in the high frequency unit 2, the signal processing unit 3, and the interface unit 4; The operation terminal 6 is used.

Further, in the multimode wireless device of this example, a DSP 27 program for performing signal processing and filter coefficient data corresponding to a plurality of filtering characteristics used for realizing band limiting processing on the DSP 27 program are respectively managed. Then, the filtering characteristic realized by the DSP 27 is switched by the control parameter.
Therefore, in the multimode wireless device of this example, the filtering characteristics of the wireless device can be flexibly set, changed, or added by performing the reception band limiting process by the DSP 27.

  In the multimode wireless device of this example, analog / digital conversion means is configured by the function of the A / D converter 21, and by the function of performing quadrature detection by the oscillator 22, the phase shifter 23, and the multipliers 24a and 24b. The detection means is configured, and the digital signal processing means is configured by the functions of the DSP 27 having the functions of the band limiting filters 31a and 31b and the function of the demodulator 32. The operation terminal 6 and the CPUs 52 and 28 provide the DSP 27 with respect to the DSP 27. The filtering characteristic determination data supply means is configured by the function of supplying control parameter data for determining the filtering characteristic. In this example, filter coefficients h (1), h (2),..., H (TAP) of an FIR type digital filter are used as data for determining the filtering characteristics.

Here, the configuration of the wireless device or the like according to the present invention is not necessarily limited to the above-described configuration, and various configurations may be used. The present invention can also be provided as, for example, a method or method for executing the processing according to the present invention, a program for realizing such a method or method, or a recording medium for recording the program. It is also possible to provide various devices and systems.
The application field of the present invention is not necessarily limited to the above-described fields, and the present invention can be applied to various fields.
In addition, as various processes performed in the wireless device according to the present invention, for example, control is performed by executing a control program stored in a ROM (Read Only Memory) by a processor in a hardware resource including a processor, a memory, and the like. For example, each functional unit for executing the processing may be configured as an independent hardware circuit.
The present invention can also be understood as a computer-readable recording medium such as a floppy (registered trademark) disk or a CD (Compact Disc) -ROM storing the control program, and the program (itself). The processing according to the present invention can be performed by inputting the program from the recording medium to the computer and causing the processor to execute the program.

It is a figure which shows the structural example of the multimode radio | wireless apparatus which concerns on one Example of this invention. It is a figure which shows an example of the control parameter passed from CPU to DSP. It is a figure which shows an example of the procedure of the process performed by DSP. It is a figure which shows the structural example of a multimode radio | wireless machine.

Explanation of symbols

  1, 61 ··· Antenna, 2, 62 ·· High-frequency unit, 3, 63 ·· Signal processing unit, 4, 64 ·· Interface unit, 5, 65 ·· Control unit, 6, 66 ·· 71..Receiver, 12, 28, 42, 52, 75, 92, 102 ..CPU, 21, 81 ..A / D converter, 22, 82 ..Oscillator, 23, 83 ..Phase shifter, 24a, 24b, 84a, 84b ... multiplier, 25a, 25b, 85a, 85b ... low band limiting filter, 26a, 26b, 86a, 86b ... down converter, 27, 87 ... DSP, 31a, 31b, 73a 73b, 73c, band limiting filter, 32, demodulator, 41, 91, audio D / A converter, 51, 101, radio control unit, 72, 74, switch,

Claims (1)

In a radio that processes received signals,
Analog-to-digital conversion means for converting a received signal from an analog signal to a digital signal;
Detection means for detecting the received signal converted into a digital signal by the analog-digital conversion means;
Digital signal processing having a function of performing a filtering process for limiting a signal band by digital signal processing and band-limiting a signal obtained as a result of detection by the detection means, and a function of demodulating the signal after the band limitation by digital signal processing Means,
Filtering characteristic determination data supply means for supplying data for determining a filtering characteristic of the filtering processing to the digital signal processing means,
The digital signal processing means executes a filtering process of a filtering characteristic determined by data supplied by the filtering characteristic determination data supply means by digital signal processing;
A wireless device characterized by that.

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