JP2009212999A - Correction data acquisition method and circuit, and receiving apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a correction data acquisition method and circuit and a receiving apparatus, capable of improving performance of the receiving apparatus including an amplifier circuit, by accurately correcting a signal output from the amplifier circuit. <P>SOLUTION: A correction data acquisition circuit includes: at least a reference signal generator 9 which outputs a reference signal; an amplifier circuit 3 which amplifies and outputs the reference signal; an A/D conversion unit 6 which performs A/D conversion upon the amplified signal and branches and outputs the signal into two systems; a band limit filter 10 which outputs a signal of one system while performing band limiting thereon; a correction processing section 7 which acquires correction data for correcting the output of the amplifier circuit 3 on the basis of a band-limited signal and a band-non-limited signal; and a correction data storage section 8 for storing the correction data so as to refer to them. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a correction data acquisition method, a correction data acquisition circuit, and a receiving apparatus, and more particularly to a correction data acquisition method for acquiring correction data for correcting distortion of an output waveform caused by nonlinearity of gain of an amplifier circuit, and The present invention relates to a correction data acquisition circuit and a receiving apparatus that performs correction using the correction data.

  In a receiving apparatus that receives a weak radio wave or the like, an amplifier circuit is used to amplify a received signal (for example, Patent Documents 1 and 2 below).

  FIG. 3 is a diagram illustrating an example of input / output characteristics of the amplifier circuit. The amplifier circuit has a function of amplifying the input signal by a certain amount, but ideally, when the input increases at a constant rate, the output also increases at the same rate, as shown by the broken line in the figure. However, in the amplifier circuit, when the magnitude of the input signal exceeds a certain value, the output characteristics deteriorate, and as shown by the solid line in the figure, there occurs a region where the output signal is not proportional to the increase of the input signal.

  FIG. 4 is a diagram illustrating an example of an output signal of an amplifier circuit when a sine wave having an input level with which the output signal is not proportional is input. The output signal of the amplifier circuit should ideally have the waveform shown by the broken line in the figure, but as described above, the output characteristics deteriorate when the magnitude of the input signal exceeds a certain value. As shown by the solid line in the figure, the waveform is distorted.

JP 200251090 A JP 2001-168664 A

  As a method for improving the nonlinearity of the gain of such an amplifier circuit, there is a method using a gain equalizer. However, in the wideband receiver, since harmonic components are superimposed on the output signal, waveform distortion cannot be improved even if a gain equalizer is used, and the signal output from the amplifier circuit cannot be accurately corrected. There was a problem.

  As another method, a correction method including calculation prediction can be considered. However, this correction method has a limit for the following reason.

  FIG. 5 is a diagram illustrating an example of theoretical values and input / output waveforms of the amplifier circuit in the receiving device when a sine wave generated by the reference signal generator is input. In the reference signal generator, there is a slight frequency error in the output signal with respect to the set frequency, so the input waveform of the amplifier circuit indicated by the broken line is estimated from the sine wave obtained from the theoretical characteristics indicated by the thin solid line in the figure. It was difficult to do. This is because it is necessary to correct the frequency error included in the reference signal and synchronize the phase information of the input data with the output waveform of the amplifier circuit to be acquired.

  As described above, since it is difficult to obtain the input signal to the amplifier circuit indicated by the broken line and the output signal distorted by the characteristic of the amplifier circuit indicated by the thick solid line, it is difficult to obtain the input / output characteristics of the amplifier circuit. There is a problem that the signal output from the amplifier circuit cannot be corrected accurately even if a correction method that cannot be obtained and calculation prediction is used.

  The present invention has been made in view of the above problems, and its main purpose is to correct the signal output from the amplifier circuit accurately and to improve the performance of the receiving device including the amplifier circuit. The object is to provide a data acquisition method, a correction data acquisition circuit, and a receiving apparatus.

  In order to achieve the above object, a correction data acquisition method according to the present invention includes a process of amplifying a reference signal by an amplifier circuit, a process of A / D converting the amplified signal, and two A / D converted signals. Correction data for correcting the output of the amplifier circuit based on a process of branching to a system and band-limiting a signal of one system with a band-limiting filter and a band-limited signal and a signal that is not band-limited And at least a process for storing the correction data in a referable manner.

  In the present invention, the band limiting filter reduces harmonic components caused by waveform distortion due to the characteristics of the amplifier circuit, and the signal of the one system can be approximated as an input waveform of the amplifier circuit. It can be set as the structure converted.

  The correction data acquisition circuit of the present invention includes a reference signal generator that outputs a reference signal, an amplifier circuit that amplifies and outputs the reference signal, and A / D-converts the amplified signal into two systems. Based on an A / D converter that outputs the signal after branching, a band limiting filter that band-limits and outputs a signal of one system, and a signal that is band-limited and a signal that is not band-limited. The image processing apparatus includes at least a correction processing unit that acquires correction data for correcting an output, and a correction data storage unit that stores the correction data so that the correction data can be referred to.

  Further, the present invention is a receiving device including at least the amplifier circuit, a correction processing unit, and a correction data storage unit, wherein the correction data is stored in the correction data storage unit so that the correction data can be referred to, and the correction processing unit Refers to correction of a signal output from the amplifier circuit with reference to correction data stored in the correction data storage unit.

  According to the correction data acquisition method, the correction data acquisition circuit, and the reception device of the amplifier circuit of the present invention, it is possible to accurately correct the signal output from the amplifier circuit and improve the performance of the reception device including the amplifier circuit.

  The reason is that the input / output characteristics of the amplifier circuit can be accurately measured by eliminating the harmonic components using a narrow band limiting filter and obtaining a signal equivalent to the input signal to the amplifier circuit. It is. Then, by reflecting the measurement result, it is possible to appropriately correct deterioration due to distortion of the output signal of the amplifier circuit.

  As shown in the background art, an amplifier circuit for amplifying a received signal is usually used for a receiving device. When the input signal becomes a certain level or more due to the input / output characteristics of the amplifier circuit, the amplifier circuit is used. Output signal is distorted. Therefore, in order to accurately correct the output signal of the amplifier circuit, it is necessary to acquire the input / output characteristics of the amplifier circuit, but the conventional measurement method cannot accurately know the condition of the input signal of the amplifier circuit. Therefore, it is difficult to obtain correction data.

  Therefore, in the present invention, a waveform that can be approximated as an input waveform of the amplifier circuit 3 is obtained by inputting a sine wave to the amplifier circuit and subjecting the data after A / D conversion to a narrow-band band limiting filter process. Then, by comparing the signal that has been subjected to the band limiting filter processing with the signal that has not been subjected to the band limiting filter processing, the input / output characteristics of the amplifier circuit can be obtained, and the signal output from the amplifier circuit can be accurately corrected. To do.

  In order to describe the above-described embodiment of the present invention in further detail, a correction data acquisition method, a correction data acquisition circuit, and a receiving apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram illustrating a configuration example of a correction data acquisition circuit according to the present exemplary embodiment, and FIG. 2 is a block diagram illustrating a configuration example of a receiving apparatus. Moreover, FIG. 6 is a figure for demonstrating the effect of a present Example.

  As shown in FIG. 1, the correction data acquisition circuit of this embodiment includes a reference signal generator 9 that outputs a reference signal (for example, a sine wave) for obtaining correction data, and an amplifier circuit 3 that amplifies the reference signal. An A / D converter 6 that converts the amplified signal into a digital signal, a narrow band-pass filter (BPF: Band-pass filter) 10 that reduces harmonic components, and a signal output from the amplifier circuit 3 Is provided with at least a correction processing unit 7 that acquires correction data for correcting the correction and performs correction processing using the correction data, and a correction data storage unit 8 that stores the correction data in a referable manner.

  The output signal of the reference signal generator 9 is input to the amplifier circuit 3. The output signal of the amplifier circuit 3 is input to the A / D converter 6. The output signal of the A / D conversion unit 6 is branched into two systems, one is directly input to the correction processing unit 7, and the other is input to the correction processing unit 7 through the narrow band limiting filter 10. Then, correction data is acquired by the correction processing unit 7 based on the two systems of signals, and the correction data is output to the correction data storage unit 8.

  The correction data is data for correcting a signal output from the amplifier circuit 3 by a receiving device to be described later, and the correction data may be the two systems of signals themselves or acquired from these signals. The input / output characteristic of the amplifier circuit 3 may be used, or may be a correction coefficient calculated from the input / output characteristic of the amplifier circuit 3 (value multiplied by the signal output from the amplifier circuit 3 by the receiving device). . The band limited by the narrow band limiting filter 10 can be set as appropriate according to the input / output characteristics of the amplifier circuit 3, and is not particularly limited.

  Hereinafter, a correction data acquisition method using the correction data acquisition circuit of this embodiment will be described in detail with reference to FIG.

  The sine wave output from the reference signal generator 9 is amplified by the amplifier circuit 3, converted into a digital signal by the A / D conversion unit 6, and input to the correction processing unit 7. Here, the output signal of the A / D converter 6 is affected by the input / output characteristics of the amplifier circuit 3, and a sine wave having an input level equal to or greater than a certain value is distorted as shown by a thick solid line waveform in FIG. End up. The distorted portion of the sine wave is observed as a harmonic component in the frequency domain.

  Therefore, in this embodiment, a narrow-band band limiting filter 10 is disposed between one path of the A / D converter 6 and the correction processing unit 7, and the output of the reference signal generator 9 is supplied to the correction processing unit 7. For each level, a signal directly output from the A / D conversion unit 6 and a signal output from the A / D conversion unit 6 through the narrow band limiting filter 10 are input.

  As shown in FIG. 6, the narrow-band band limiting filter 10 can reduce the harmonic component of the signal distorted by the amplifier circuit 3, so that a waveform that can be approximated as the input waveform of the amplifier circuit 3 is obtained. Can do. Further, since the processing delay time of the narrow band limiting filter 10 can be determined from the filter design, the input / output signal of the narrow band limiting filter 10 can be extracted as a signal synchronized in the time domain.

  Therefore, the correction processing unit 7 does not receive the influence of the error included in the reference signal generator 9 and the signal output directly from the A / D conversion unit 6 and the band limitation of the narrow band from the A / D conversion unit 6. Based on the signal output through the filter 10, the input / output characteristics of the amplifier circuit 3 can be accurately measured, and accurate correction data can be obtained.

  Then, the correction processing unit 7 outputs the acquired correction data to the correction data storage unit 8, and the correction data storage unit 8 stores the correction data in a referable manner.

  FIG. 1 shows an example of the correction data acquisition circuit according to the present embodiment. As long as the signal subjected to the band limitation filter processing and the signal not subjected to the band limitation filter processing are configured to be comparable, the circuit configuration is illustrated. Can be appropriately changed.

  Next, a receiving apparatus that uses the correction data acquired in the above procedure will be described.

  FIG. 2 is a diagram illustrating an example of a wideband receiving apparatus. The broadband receiving device synchronizes the signals received by the antenna device 1 that receives radio waves, the local transmitter 4 that generates local signals, the control processing unit 5 that controls the local transmitter 4, and the signals received by the antenna device 1 with local signals. Quadrature detector 2 for detecting, amplifier circuit 3 for amplifying the output of quadrature detector 2, A / D converter 6 for converting the output signal of amplifier circuit 3 into a digital signal, and output of A / D converter 6 A correction processing unit 7 that corrects a signal and a correction data storage unit 8 that stores correction data acquired by the above procedure are provided.

  That is, in the measurement system shown in FIG. 2, an antenna device 1 that outputs an incoming radio wave to be observed is connected instead of the reference signal generator 9 of FIG. Further, in order to measure a wideband signal, the narrowband band limiting filter 10 is removed.

  At the time of reception of the wideband signal, the correction processing unit 7 from the correction data storage unit 8 uses the reception frequency set by the control processing unit 5 and the power value actually observed at the output of the A / D conversion unit 6. With reference to the correction data, the processing result of the received signal is output after the correction calculation. Thereby, deterioration due to distortion of the output signal of the amplifier circuit 3 can be appropriately corrected, and the performance of the receiving apparatus can be improved.

  In the receiving apparatus of FIG. 2, the reference signal generator 9 and the narrow-band band limiting filter 10 are arranged only when the correction data is acquired and the correction data is acquired. However, the correction data acquisition circuit is incorporated in the receiving apparatus. You can also.

  In that case, for example, a changeover switch or the like is disposed between the front stage of the amplifier circuit 3 and the A / D conversion unit 6 and the narrowband band limiting filter 10 and is switched by the control signal, so that the antenna apparatus 1 receives the signal. When processing a wideband signal, the output of the quadrature detector 2 is transmitted to the amplifier circuit 3, the A / D conversion unit 6, and the correction processing unit 7 as in FIG. The output from the reference signal generator 9 is input to the amplifier circuit 3, and a part of the output of the A / D conversion unit 6 is input to the correction processing unit 7 through the narrow band limiting filter 10. What should I do?

  In the above embodiment, the correction data acquisition circuit of the present invention is applied to a receiving device that receives radio waves. However, the present invention is not limited to the above embodiment, and an arbitrary circuit including an amplifier circuit may be used. The present invention can be similarly applied to these devices.

  Moreover, although the case where the correction data of the amplifier circuit 3 is acquired has been described in the above embodiment, the target for acquiring the correction data is not limited to the amplifier circuit 3, but an arbitrary circuit whose output characteristics fluctuate according to the input level. It can be applied to.

  INDUSTRIAL APPLICABILITY The present invention can be used for a correction data acquisition method and a correction data acquisition circuit for correcting a signal, and an apparatus for correcting a signal using correction data.

It is a block diagram which shows the structure of the correction data acquisition circuit based on one Example of this invention. It is a block diagram which shows the structure of the receiver which concerns on one Example of this invention. It is a figure which shows the input-output characteristic of an amplifier circuit. It is a figure for demonstrating the distortion of a received signal by the input / output characteristic of an amplifier characteristic. It is a figure which shows the relationship between a reference signal and the input-output waveform of an amplifier circuit. It is a figure for demonstrating the effect of the band-limiting filter of a narrow band.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Antenna apparatus 2 Quadrature detector 3 Amplifier circuit 4 Local transmitter 5 Control processing part 6 A / D conversion part 7 Correction processing part 8 Correction data 9 Reference signal generator 10 Narrow-band band-limiting filter (BPF)

Claims (5)

A process of amplifying the reference signal with an amplifier circuit;
A process of A / D converting the amplified signal;
A process of branching the A / D converted signal into two systems and band-limiting the signal of one system with a band-limiting filter;
Processing for obtaining correction data for correcting the output of the amplifier circuit based on a band-limited signal and a signal that is not band-limited;
The correction data acquisition method characterized by performing at least the process of storing the correction data in a referenceable manner.   The band limiting filter reduces harmonic components due to waveform distortion due to the characteristics of the amplifier circuit, and converts the signal of the one system into a waveform that can be approximated as an input waveform of the amplifier circuit. The correction data acquisition method according to claim 1, wherein: A reference signal generator for outputting a reference signal;
An amplifier circuit that amplifies and outputs the reference signal;
An A / D converter that A / D-converts the amplified signal and branches and outputs the two signals; and
A band limiting filter for band limiting the signal of one system and outputting it;
A correction processing unit that acquires correction data for correcting the output of the amplifier circuit based on a band-limited signal and a signal that is not band-limited;
A correction data acquisition circuit comprising at least a correction data storage unit that stores the correction data in a referable manner.   The band limiting filter has a function of reducing harmonic components due to waveform distortion due to characteristics of the amplifier circuit and converting the signal of the one system into a waveform that can be approximated as an input waveform of the amplifier circuit. The correction data acquisition circuit according to claim 3. A receiving device comprising at least the amplifier circuit according to claim 3, a correction processing unit, and a correction data storage unit,
In the correction data storage unit, the correction data is stored so that it can be referred to.
The receiving apparatus, wherein the correction processing unit performs correction of a signal output from the amplifier circuit with reference to correction data stored in the correction data storage unit.

Images