RECEPTION DEVICE AND A/D CONVERSION METHOD

Abstract

A reception device includes: a first A/D converter to convert the input analog information signal into a first digital information signal by A/D conversion to output it,; an analog amplifier to amplify the input analog information signal to output it; a second A/D converter to convert the analog information amplification signal output from the analog amplifier into a second digital information signal by A/D conversion to output it; a frequency characteristic corrector to output a second digital information correction signal obtained by correcting the second digital information signal output from the second A/D converter based on a frequency-dependent input/output characteristic of the analog amplifier; and an information signal selector and outputter to select and output, as a digital information signal, either the first digital information signal output from the first A/D converter or the second digital information correction signal output from the frequency characteristic corrector.

Description

Claims

1. A reception device comprising: a first A/D converter to receive an analog information signal, convert the input analog information signal into a first digital information signal by A/D conversion, and output the first digital information signal;an analog amplifier to receive the analog information signal, amplify the input analog information signal, and output an analog information amplification signal;a second A/D converter to convert the analog information amplification signal output from the analog amplifier into a second digital information signal by A/D conversion and output the second digital information signal;a frequency characteristic corrector to output a second digital information correction signal obtained by correcting the second digital information signal output from the second A/D converter based on a frequency-dependent input/output characteristic of the analog amplifier; andan information signal selector and outputter to select and output, as a digital information signal, either the first digital information signal output from the first A/D converter or the second digital information correction signal output from the frequency characteristic corrector.

2. The reception device according to claim 1, wherein the frequency characteristic corrector includes: a fast Fourier transformer to transform the second digital information signal output from the second A/D converter from a time domain signal into a frequency domain signal by Fourier transform;a waveform corrector to correct the second digital information signal which has been subjected to Fourier transform by the fast Fourier transformer using the frequency-dependent input/output characteristic of the analog amplifier; andan inverse fast Fourier transformer to transform the second digital information signal corrected by the waveform corrector from a frequency domain signal to a time domain signal by inverse Fourier transform and output the second digital information signal as the second digital information correction signal.

3. The reception device according to claim 2, wherein a correction value of the frequency-dependent input/output characteristic of the analog amplifier used in the waveform corrector is set by inputting an analog test signal to the analog amplifier and measuring an analog amplification signal output from the analog amplifier.

4. The reception device according to claim 1, wherein the frequency characteristic corrector is a waveform shaping filter having a characteristic of changing a pass band by a filter coefficient, the waveform shaping filter correcting the second digital information signal output from the second A/D converter by changing the filter coefficient corresponding to the frequency-dependent input/output characteristic of the analog amplifier, and outputting the corrected second digital information signal as the second digital information correction signal.

5. The reception device according to claim 4, wherein the filter coefficient used for the waveform shaping filter is set by inputting an analog test signal to the analog amplifier and measuring a digital test correction signal output from the waveform shaping filter.

6. The reception device according to claim 1, further comprising a delay adjuster provided in a preceding stage of the first A/D converter, the delay adjuster adjusting a timing at which the analog information signal is input to the first A/D converter to a timing at which the analog information amplification signal is input to the second A/D converter.

7. The reception device according to claim 6, wherein the delay adjuster adjusts a delay amount by a delay amount control signal based on an ambient temperature detected by a temperature sensor.

8. The reception device according to claim 7, wherein the delay amount to be adjusted in the delay adjuster is set by inputting a delay amount setting signal to the delay adjuster and the analog amplifier, and measuring timings at which the delay amount setting signal is input to the first A/D converter and the second A/D converter while changing an ambient temperature.

9. An A/D conversion method comprising: converting an analog information signal into a first digital information signal by A/D conversion and outputting the first digital information signal by a first A/D converter;amplifying the analog information signal and outputting an analog information amplification signal by an analog amplifier;converting the analog information amplification signal into a second digital information signal by A/D conversion and outputting the second digital information signal by a second A/D converter;outputting, by a frequency characteristic corrector, a second digital information correction signal obtained by correcting the second digital information signal based on a frequency-dependent input/output characteristic of the analog amplifier; andselecting and outputting, as a digital information signal, either the first digital information signal or the second digital information correction signal by an information signal selector and outputter.

10. The A/D conversion method according to claim 9, wherein the frequency characteristic corrector includes a fast Fourier transformer, a waveform corrector, and an inverse fast Fourier transformer, andthe outputting the second digital information correction signal includes: transforming, by the fast Fourier transformer, the second digital information signal from a time waveform into a frequency spectrum by Fourier transform;correcting, by the waveform corrector, the second digital information signal that has been subjected to Fourier transform using the frequency-dependent input/output characteristic of the analog amplifier; andtransforming the second digital information signal which has been corrected from a frequency spectrum to a time waveform by inverse Fourier transform and outputting the second digital information signal as the second digital information correction signal by the inverse fast Fourier transformer.

11. The A/D conversion method according to claim 9, wherein the frequency characteristic corrector is a waveform shaping filter having a characteristic of changing a pass band by a filter coefficient, andthe outputting the second digital information correction signal includes correcting the second digital information signal by changing the filter coefficient corresponding to the frequency-dependent input/output characteristic of the analog amplifier, and outputting the corrected second digital information signal as the second digital information correction signal by the waveform shaping filter.