Waveform generator operable in accordance with a plurality of band limitation characteristics

• US 7,120,204 B2
• Filed: 12/12/2001
• Issued: 10/10/2006
• Est. Priority Date: 01/10/2001
• Status: Expired due to Fees

• Current Assignee: Socionext Inc.
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Matsusaka, Hiromi
• Primary Examiner(s): Deppe, Betsy L.
• Application Number:
  US10/012,325
• Publication Number:
  US 20020090036A1
• Time in Patent Office: 1,763 Days
• Field of Search: 375/237, 375/240, 375/212, 375/213, 375/200, 375/261, 375/271, 375/279, 375/280, 375/281, 375/302, 375/308, 332/103, 332/145
• US Class Current: 375/302
• CPC Class Codes: G06F 1/0321 Waveform generators, i.e. devices for generating periodical functions of time, e.g. direct digital synthesizers G06F1/0314, G06F1/035 take precedence
• CPC Class Codes: H03H 17/0607 comprising a ROM addressed by the input data signals

Abstract

A waveform generator comprises waveform generating means for generating a waveform signal band-limited using a first band limitation characteristic in accordance with the input signal series, memory means for storing in advance a difference signal between a waveform signal band-limited using the first band limitation characteristic for the input signal series and a waveform signal band-limited using a second band limitation characteristic for the input signal series and outputting the difference signal in accordance with the input signal series, adding means for adding a waveform signal from the waveform generating means to a difference signal from the memory means and outputting the signal band-limited using the second band limitation characteristic, and selector switch means for selectively outputting either a waveform signal from the waveform generating means or a waveform signal from the adding means.

Claims

1. A waveform generator for quadrature modulation operable in accordance with a plurality of band limitation characteristics, comprising:

serial-to-parallel conversion means for converting serial transmission data to parallel data;

mapping means for converting parallel data from said serial-to-parallel conversion means to amplitude-phase information and outputting the information as I-channel symbol data and Q-channel symbol data;

first waveform generating means for generating a waveform signal band-limited using a first band limitation characteristic in accordance with said I-channel symbol data from said mapping means;

first memory means for storing in advance a difference signal between a waveform signal band-limited using the first band limitation characteristic for said I-channel symbol data and a waveform signal band-limited using a second band limitation characteristic for said I-channel symbol data and outputting said difference signal in accordance with said I-channel symbol data;

first adding means for adding the waveform signal from said first waveform generating means to the difference signal from said first memory means and outputting the waveform signal band-limited using the second band limitation characteristic for said I-channel symbol data;

first selector switch means for selectively outputting either the waveform signal from said first waveform generating means or the waveform signal from said first adding means;

second waveform generating means for generating a waveform signal band-limited using a first band limitation characteristic in accordance with Q-channel symbol data from said mapping means;

second memory means for storing in advance a difference signal between a waveform signal band-limited using the first band limitation characteristic for said Q-channel symbol data and a waveform signal band-limited using a second band limitation characteristic for said Q-channel symbol data and outputting said difference signal in accordance with said symbol data;

second adding means for adding the waveform signal from said second waveform generating means to said difference signal from said second memory means and outputting the waveform signal band-limited using the second band limitation characteristic for said Q-channel symbol data; and

second selector switch means for selectively outputting either the waveform signal from said second waveform generating means or the waveform signal from said second adding means.