Receiver and wireless communication system equipped with the same
A receiver includes: an amplifier that amplifies a received broadband signal up to a predetermined level; a first switch that switches an output signal from the amplifier; a signal generator that generates a signal for controlling a switching operation of the first switch; an integration capacitor that integrates an output signal from the first switch; a comparator that compares an output voltage from the integration capacitor with a predetermined voltage; and a reset circuit that discharges electrical charges accumulated in the integration capacitor based on a comparison result from the comparator.
1. A receiver comprising:
an amplifier that amplifies a received broadband signal up to a predetermined level;
a first switch that switches an output signal from the amplifier;
a signal generator that generates a signal for controlling a switching operation of the first switch;
an integration capacitor that integrates an output signal from the first switch;
a comparator that compares an output voltage from the integration capacitor with a predetermined voltage; and
a reset circuit that discharges electrical charges accumulated in the integration capacitor based on a comparison result from the comparator.
2. The receiver according to claim 1 , wherein the broadband signal is a pulse radio frequency signal.
3. The receiver according to claim 2 , further comprising:
a voltage supply that supplies the comparator with a first comparison voltage for detecting a positive correlation with the broadband signal and a second comparison voltage for detecting a negative correlation with the broadband signal; and
a controller that controls the voltage supply so that values of the first comparison voltage and the second comparison voltage become narrower in stages.
4. The receiver according to claim 2 , further comprising:
a voltage supply that supplies the comparator with a first comparison voltage for detecting a positive correlation with the broadband signal and a second comparison voltage for detecting a negative correlation with the broadband signal; and
a controller that controls the voltage supply so that values of the first comparison voltage and the second comparison voltage vary according to a binary search method.
5. The receiver according to claim 2 , wherein the comparator includes
a plurality of comparator elements that compare an output voltage of the integration capacitor with a comparison voltage that is a preset predetermined voltage, and
a receiver that further comprises a voltage supply that supplies comparison voltages that are respectively different from each other to the plurality of comparator elements.
6. The receiver according to claim 2 , wherein the amplifier includes an inductor to be connected between a power supply potential and an output terminal.
7. The receiver according to claim 2 , wherein the amplifier includes a cascode-structure transistor to be connected between a ground potential and an output terminal.
8. A wireless communication system comprising:
a transmitter for transmitting a broadband signal; and
the receiver according to claim 2 which receives the broadband signal.
9. The receiver according to claim 1 , further comprising:
a voltage supply that supplies the comparator with a first comparison voltage for detecting a positive correlation with the broadband signal and a second comparison voltage for detecting a negative correlation with the broadband signal; and
a controller that controls the voltage supply so that values of the first comparison voltage and the second comparison voltage vary according to a binary search method.
10. The receiver according to claim 1 , wherein the comparator includes
a plurality of comparator elements that compare an output voltage of the integration capacitor with a comparison voltage that is a preset predetermined voltage, and
a receiver that further comprises a voltage supply that supplies comparison voltages that are respectively different from each other to the plurality of comparator elements.
11. The receiver according to claim 1 , wherein the amplifier includes an inductor to be connected between a power supply potential and an output terminal.
12. The receiver according to claim 1 , wherein the amplifier includes a cascode-structure transistor to be connected between a ground potential and an output terminal.
13. The receiver according to claim 1 , wherein:
the broadband signal is an MB-OFDM signal;
the receiver further comprising
a second switch that supplies the reset circuit with a reset signal for discharging electrical charges accumulated in the integration capacitor at predetermined time intervals generated by the signal generator; and
a controller that controls switching operations of the second switch.
14. A wireless communication system comprising:
a transmitter for transmitting a broadband signal; and
the receiver according to claim 1 which receives the broadband signal.
15. A receiver comprising:
an amplifier that amplifies a received broadband signal up to a predetermined level;
a first switch that switches an output signal from the amplifier;
a signal generator that generates a signal for controlling a switching operation of the first switch;
an integration capacitor that integrates an output signal from the first switch;
a comparator that compares an output voltage from the integration capacitor with a predetermined voltage;
a reset circuit that discharges electrical charges accumulated in the integration capacitor based on a comparison result from the comparator;
a voltage supply that supplies the comparator with a first comparison voltage for detecting a positive correlation with the broadband signal and a second comparison voltage for detecting a negative correlation with the broadband signal; and
a controller that controls the voltage supply so that values of the first comparison voltage and the second comparison voltage become narrower in stages.
16. A wireless communication system comprising:
a transmitter for transmitting a broadband signal; and
the receiver according to claim 15 which receives the broadband signal.
17. A reception method comprising:
amplifying a received broadband signal up to a predetermined level;
switching the amplified signal at a predetermined frequency using a switching element;
directly integrating the switched signal using an integration capacitor;
comparing the integrated voltage with a predetermined voltage using a comparator; and
resetting a voltage corresponding to electrical charges accumulated by the integration operation based on the comparison result.
18. The method according to claim 17 , further comprising switching between demodulation of a pulse radio frequency signal that is the broadband signal and demodulation of an MB-OFDM signal that is the broadband signal.
19. The method according to claim 18 , further comprising receiving pulse radio frequency signals at predetermined time intervals even when participating in an MB-OFDM beacon group.
20. The method according to claim 18 , further comprising receiving MB-OFDM signals at predetermined time intervals even when an MB-OFDM signal beacon group is not being detected.