Signal generating apparatus
AssigneeKabushiki Kaisha Toshiba
InventorAkira Yasuda
Life of this patent
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Abstract
A signal generating apparatus comprises a mapping circuit for converting a time-sequential input signal into I and Q signals constituting a QPSK code, a signal holding circuit for dividing each of I and Q signals into a plurality of digital signals, retaining them, and outputting them in parallel, a waveform forming circuit for outputting waveform data items corresponding to the plurality of digital signals from the signal holding circuit, a D/A converter for converting the waveform data items from the waveform forming circuit into a plurality of analog signals, an adder for adding the plurality of analog signals from the D/A converter and outputting a sum signal, and a filter for eliminating unwanted frequency components from the sum signal from the adder.
Claims15
A signal generating apparatus comprising:
- signal conversion means for converting a time-sequential input signal into a time-sequential digital signal;
- signal holding means for dividing the time-sequential digital signal from said signal conversion means into a plurality of digital signals, retaining said signals, and outputting said signals in parallel;
- waveform forming means for outputting a plurality of waveform data corresponding to the plurality of digital signals from said signal holding means respectively;
- a current conversion-type D/A converter for converting the plurality of waveform data from said waveform forming means into a plurality of current signals;
- addition means for adding the plurality of current signals from said D/A conversion means and outputting a sum signal;
- and
- filter means for removing predetermined high frequency components from the sum signal from said addition means.
A signal generating apparatus comprising:
- signal conversion means for converting a time-sequential input signal into a time-sequential digital signal;
- signal holding means for dividing the time-sequential digital signal from said signal conversion means into a plurality of digital signals including a first and a second digital signal, retaining the signals, and outputting the signals in parallel;
- waveform forming means which contains a plurality of memories for storing a plurality of .DELTA..SIGMA. modulation data corresponding to the plurality of digital signals from said signal holding means, respectively;
- a current conversion-type D/A converter for converting the plurality of .DELTA..SIGMA. conversion data from said plurality of memories into a plurality of current signals;
- addition means for adding the plurality of current signals from said D/A conversion means and outputting a sum current signal;
- and
- filter means for removing predetermined frequency components from the sum current signal from said addition means.
A signal generating apparatus comprising:
- signal conversion means for converting a time-sequential input signal into a time-sequential digital signal;
- signal holding means for dividing the time-sequential digital signal from said signal conversion means into a plurality of digital signals, retaining them, and outputting them in parallel;
- plurality of waveform forming means for outputting plurality of waveform data corresponding to the plurality of digital signals from said signal holding means respectively;
- D/A conversion means for converting the waveform data items from said waveform forming means into a plurality of analog signals;
- weighting means for multiplying each of the plurality of analog signals from said D/A conversion means by a weighting coefficient according to a waveform of each of the analog signals, and outputting a weighted analog signal;
- addition means for adding the weighted analog signals from said weighting means and outputting a sum signal;
- and
- filter means for removing predetermined high frequency components from the sum signal from said addition means.
Dependencies are inferred from the claim text.