Correlator And Ultrawideband Radio Receiving Apparatus Incorporating The Same
First Claim
1. A correlator comprising:
- (a) a plurality of delay elements that are connected in series and each output an output signal, the delay element includinga delay line configured by a plurality of delay-line elements that are connected in series, the delay-line element being a low pass filter that has an inductor and a capacitor andan amplifier that compensates for a loss that occurs in the delay line so that an output voltage of the delay element is equal to an input voltage of the delay element;
the amplifier havingan input connected to an output of the delay-line element constituting a last stage of the delay line so such that impedance matching is obtained between the delay line and the amplifier andan output connected to an input of a subsequent circuit such that the impedance matching is obtained between the amplifier and the subsequent circuit;
(b) a plurality of multipliers having a predetermined coefficient of either +1 or −
1 and each configured to multiply corresponding each of the output signals supplied from the delay elements by the predetermined coefficient; and
(c) an adder that sums the output signals that have been multiplied by the predetermined coefficient.
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Abstract
A correlator (i.e., a despreading filter) and an ultrawideband radio receiving apparatus that incorporates the correlator are provided. In one embodiment, a correlator multiplies a plurality of output signals output by a plurality of delay elements that are series-connected by a predetermined coefficient of either +1 or −1 and then sums the plurality of output signals, the delay element including a delay line and an amplifier; the delay line being configured by serially connecting a plurality of delay-line elements, each of the delay-line elements being a low pass filter that has an inductor and a capacitor; the amplifier being connected to an output of a last-stage delay-line element of the series-connected delay-line elements so as to perform impedance matching with respect to the delay line; an output of the amplifier being connected to a subsequent circuit so as to perform impedance matching with respect to the subsequent circuit, such that a loss of the delay line is compensated for and an output voltage of the delay element is made equal to an input voltage of the delay element.
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Citations
3 Claims
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1. A correlator comprising:
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(a) a plurality of delay elements that are connected in series and each output an output signal, the delay element including a delay line configured by a plurality of delay-line elements that are connected in series, the delay-line element being a low pass filter that has an inductor and a capacitor and an amplifier that compensates for a loss that occurs in the delay line so that an output voltage of the delay element is equal to an input voltage of the delay element; the amplifier having an input connected to an output of the delay-line element constituting a last stage of the delay line so such that impedance matching is obtained between the delay line and the amplifier and an output connected to an input of a subsequent circuit such that the impedance matching is obtained between the amplifier and the subsequent circuit; (b) a plurality of multipliers having a predetermined coefficient of either +1 or −
1 and each configured to multiply corresponding each of the output signals supplied from the delay elements by the predetermined coefficient; and(c) an adder that sums the output signals that have been multiplied by the predetermined coefficient. - View Dependent Claims (2)
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3. An ultrawideband radio receiving apparatus that performs despreading of a received spectrum-spread signal by a correlator, the correlator comprising:
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(a) a plurality of delay elements that are connected in series and each output an output signal, the delay element including a delay line configured by a plurality of delay-line elements that are connected in series, the delay-line element being a low pass filter that has an inductor and a capacitor and an amplifier that compensates for a loss that occurs in the delay line so that an output voltage of the delay element is equal to an input voltage of the delay element; the amplifier having an input connected to an output of the delay-line element constituting a last stage of the delay line such that impedance matching is obtained between the delay line and the amplifier and an output connected to an input of a subsequent circuit such that the impedance matching is obtained between the amplifier and the subsequent circuit, (b) a plurality of multipliers having a predetermined coefficient of either +1 or −
1 and each configured to multiply corresponding each of the output signals supplied from the delay elements by the predetermined coefficient; and(c) an adder that sums the output signals that have been multiplied by the predetermined coefficient.
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Specification