Channel separating filter apparatus, PSK demodulator apparatus and PSK receiver apparatus each equipped with channel separating filter apparatus
First Claim
1. A channel separating filter apparatus for separating a frequency-multiplexed signal comprised of channel signals into respective channel signals, comprising:
- frequency-converting means for frequency-converting the frequency-multiplexed signal into a plurality of channel signals, so that an average value of carrier wave frequencies of two channel signals which are located in a center of the frequency-multiplexed signal and are adjacent to each other becomes substantially zero, and for outputting the plurality of frequency-converted channel signals; and
channel separating means for separating the plurality of frequency-converted channel signals outputted from said frequency-converting means into respective channel signals each having only a frequency component of each channel signal,wherein said channel separating means comprises at least first stage filter bank, andwherein said first stage filter bank comprises;
a first positive pass filter for band-pass-filtering only a first signal having a signal component of a predetermined positive frequency from the plurality of frequency-converted channel signals outputted from said frequency-converting means, and for outputting the band-pass-filtered first signal;
first processing means for executing a first downsampling process on the band-pass-filtered first signal outputted from said first positive pass filter and for outputting a second signal including a signal of at least one channel which is obtained by the first downsampling process;
a first negative pass filter for band-pass-filtering only a third signal having a signal component of a predetermined negative frequency from the plurality of frequency-converted channel signals outputted from said frequency-converting means, and for outputting the band-pass-filtered third signal; and
second processing means for executing a second downsampling process on the band-pass-filtered third signal outputted from said first negative pass filter and for outputting a fourth signal including a signal of at least one further channel which is obtained by the second downsampling process,thereby separating the frequency-multiplexed signal into at least two channel signals.
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Abstract
There is disclosed a channel separating filter apparatus for separating a frequency-multiplexed signal comprised of channel signals into respective channel signals. A frequency-converting section frequency-converts the frequency-multiplexed signal into a plurality of channel signals, so that an average value of carrier wave frequencies of two channel signals which are located in the center of the frequency-multiplexed signal and are adjacent to each other becomes substantially zero, and then outputs the plurality of frequency-converted channel signals. Thereafter, a channel separating section separates the plurality of frequency-converted channel signals outputted from the frequency-converting section into respective channel signals each having only a frequency component of each channel signal, thereby separating the frequency-multiplexed signal into at least two channel signals.
30 Citations
6 Claims
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1. A channel separating filter apparatus for separating a frequency-multiplexed signal comprised of channel signals into respective channel signals, comprising:
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frequency-converting means for frequency-converting the frequency-multiplexed signal into a plurality of channel signals, so that an average value of carrier wave frequencies of two channel signals which are located in a center of the frequency-multiplexed signal and are adjacent to each other becomes substantially zero, and for outputting the plurality of frequency-converted channel signals; and channel separating means for separating the plurality of frequency-converted channel signals outputted from said frequency-converting means into respective channel signals each having only a frequency component of each channel signal, wherein said channel separating means comprises at least first stage filter bank, and wherein said first stage filter bank comprises; a first positive pass filter for band-pass-filtering only a first signal having a signal component of a predetermined positive frequency from the plurality of frequency-converted channel signals outputted from said frequency-converting means, and for outputting the band-pass-filtered first signal; first processing means for executing a first downsampling process on the band-pass-filtered first signal outputted from said first positive pass filter and for outputting a second signal including a signal of at least one channel which is obtained by the first downsampling process; a first negative pass filter for band-pass-filtering only a third signal having a signal component of a predetermined negative frequency from the plurality of frequency-converted channel signals outputted from said frequency-converting means, and for outputting the band-pass-filtered third signal; and second processing means for executing a second downsampling process on the band-pass-filtered third signal outputted from said first negative pass filter and for outputting a fourth signal including a signal of at least one further channel which is obtained by the second downsampling process, thereby separating the frequency-multiplexed signal into at least two channel signals. - View Dependent Claims (2, 3)
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4. A PSK receiver apparatus comprising:
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receiving means for receiving a radio signal of a frequency-multiplexed signal comprised of channel signals each being a PSK-modulated signal; a channel separating filter apparatus for separating the radio signal received by said receiving means into respective channel signals; and a PSK demodulator apparatus for demodulating the respective channel signals separated by said channel separating filter apparatus so as to generate respective demodulated channel signals, and for outputting the generated respective demodulated channel signals, and wherein said channel separating filter apparatus comprises; frequency-converting means for frequency-converting the frequency-multiplexed signal into a plurality of channel signals, so that an average value of carrier wave frequencies of two channel signals which are located in a center of the frequency-multiplexed signal and are adjacent to each other becomes substantially zero, and for outputting the plurality of frequency-converted channel signals; and channel separating means for separating the plurality of frequency-converted channel signals outputted from said frequency-converting means into respective channel signals each having only a frequency component of each channel signal, wherein said channel separating means comprises at least first stage filter bank, and wherein said first stage filter bank comprises; a first positive pass filter for band-pass-filtering only a first signal having a signal component of a predetermined positive frequency from the plurality of frequency-converted channel signals outputted from said frequency-converting means, and for outputting the band-pass-filtered first signal; first processing means for executing a first downsampling process on the band-pass-filtered first signal outputted from said first positive pass filter and for outputting a second signal including a signal of at least one channel which is obtained by the first downsampling process; a first negative pass filter for band-pass-filtering only a third signal having a signal component of a predetermined negative frequency from the plurality of frequency-converted channel signals outputted from said frequency-converting means, and for outputting the band-pass-filtered third signal; and second processing means for executing a second downsampling process on the band-pass-filtered third signal outputted from said first negative pass filter and for outputting a fourth signal including a signal of at least one further channel which is obtained by the second downsampling process, thereby separating the frequency-multiplexed signal into at least two channel signals. - View Dependent Claims (5, 6)
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Specification