Receiver
Disclosed herein is a receiver including: a first mixer adapted to mix satellite signals from first and second satellites and a first local oscillation signal so as to convert a carrier frequency of the satellite signals into a lower first intermediate frequency; a second mixer adapted to mix a satellite signal of the second satellite frequency-converted by the first mixer and a second local oscillation signal so as to convert the first intermediate frequency of the frequency-converted satellite signal from the second satellite into an even lower second intermediate frequency; and a first frequency divider adapted to generate the second local oscillation signal by dividing a frequency of the first local oscillation signal.
1. A receiver comprising:
a first mixer configured to mix a reception signal including respective satellite signals from first and second satellites and a first local oscillation signal so as to convert a carrier frequency of the respective satellite signals into a lower first intermediate frequency;
a second mixer configured to mix an output of the first mixer that corresponds to a satellite signal of the second satellite that has been frequency-converted by the first mixer and a second local oscillation signal so as to convert the first intermediate frequency of the frequency-converted satellite signal from the second satellite into an even lower second intermediate frequency;
a first frequency divider configured to generate the second local oscillation signal by dividing a frequency of the first local oscillation signal in such a manner that, of harmonic components of the second local oscillation signal, a harmonic component one higher in order than a harmonic component equal to the frequency of the first local oscillation signal falls within a carrier frequency band of the satellite signal from the second satellite; and
a signal processing circuit configured to receive an output of the first mixer that corresponds to a satellite signal of the first satellite and an output of the second mixer that corresponds to a satellite signal of the second satellite.
2. The receiver of claim 1 , wherein
the first frequency divider has a frequency division ratio identical to the order of the harmonic component, of the harmonic components of the second local oscillation signal, that is equal in frequency to the first local oscillation signal.
3. The receiver of claim 1 , further comprising
a filter configured to remove a direct-current component from the output of the second mixer that corresponds to the satellite signal from the second satellite that has been converted by the second mixer into the second intermediate frequency.
4. The receiver of claim 1 , wherein
the first satellite is a GPS (Global Positioning System) or Galileo satellite, and
the second satellite is a GLONASS (GLObal NAvigation Satellite System) satellite.
5. The receiver of claim 1 , wherein
a carrier frequency band of the first satellite is from 1573.374 to 1577.466 MHz, and
the carrier frequency band of the second satellite is from 1597.5515 to 1605.886 MHz.
6. The receiver of claim 5 , wherein
the frequency of the first local oscillation signal is 1573.000 MHz, and
a frequency division ratio of the first frequency divider is 56.
7. The receiver of claim 5 , wherein
the frequency of the first local oscillation signal is 1571.328 MHz, and
a frequency division ratio of the first frequency divider is 52.
8. The receiver of claim 1 , further comprising
a second frequency divider configured to generate a system clock by dividing the frequency of the first local oscillation signal in such a manner that a harmonic component of the system clock falls outside carrier frequency bands of the satellite signals of the first and second satellites.
9. The receiver of claim 8 , wherein
the system clock is supplied to at least one of a baseband signal processing circuit or a logic circuit including a processor, an analog-digital converter configured to convert an analog signal into a digital signal, and a converter configured to convert a given direct-current voltage into another direct-current voltage.
10. The receiver of claim 9 , wherein
the first satellite is a GPS (Global Positioning System) or Galileo satellite, and
the second satellite is a GLONASS (GLObal NAvigation Satellite System) satellite.
11. The receiver of claim 9 , wherein
the carrier frequency band of the first satellite is from 1573.374 to 1577.466 MHz, and
the carrier frequency band of the second satellite is from 1597.5515 to 1605.886 MHz.
12. The receiver of claim 11 , wherein
the frequency of the first local oscillation signal is 1573.000 MHz,
a frequency division ratio of the first frequency divider is 56, and
a frequency division ratio of the second frequency divider configured to generate the system clock supplied to the logic circuit is 11, 22 or 44, the frequency division ratio configured to generate the system clock supplied to the analog-digital converter is 44, and the frequency division ratio configured to generate the system clock supplied to the converter that converts the given direct-current voltage into the another direct-current voltage is 132.
13. The receiver of claim 11 , wherein
the frequency of the first local oscillation signal is 1571.328 MHz,
a frequency division ratio of the first frequency divider is 52, and
a frequency division ratio of the second frequency divider configured to generate the system clock supplied to the converter that converts the given direct-current voltage into the another direct-current voltage is 128.
14. The receiver of claim 1 , wherein
the first mixer is configured to separate the respective satellite signals into respective I-channel signals and respective Q-channel components based on the first local oscillation signal.
15. A receiver comprising:
a first mixer configured to mix a reception signal including respective satellite signals from first and second satellites and a first local oscillation signal so as to convert a carrier frequency of the respective satellite signals into a lower first intermediate frequency;
a second mixer configured to mix an output of the first mixer that corresponds to a satellite signal of the second satellite that has been frequency-converted by the first mixer and a second local oscillation signal so as to convert the first intermediate frequency of the frequency-converted satellite signal from the second satellite into an even lower second intermediate frequency;
a first frequency divider configured to generate the second local oscillation signal by dividing a frequency of the first local oscillation signal; and
a signal processing circuit configured to receive an output of the first mixer that corresponds to a satellite signal of the first satellite and an output of the second mixer that corresponds to a satellite signal of the second satellite, wherein
letting the frequency of the first local oscillation signal be denoted by f lo1 and a frequency division ratio of the first frequency divider by N 2 , an inequality 1597.5515 MHz<f lo1 /N 2 ×(N X +1)<1605.886 MHz is satisfied where N X is a maximum number of a natural number N that satisfies an inequality f lo1 /N 2 ×N<1573.374 MHz.
16. The receiver of claim 15 , further comprising
a filter configured to remove a direct-current component from the output of the second mixer that corresponds to the satellite signal from the second satellite that has been converted by the second mixer into the second intermediate frequency.
17. The receiver of claim 15 , wherein
the first satellite is a GPS (Global Positioning System) or Galileo satellite, and
the second satellite is a GLONASS (GLObal NAvigation Satellite System) satellite.
18. The receiver of claim 15 , further comprising
a second frequency divider configured to generate a system clock by dividing the frequency of the first local oscillation signal in such a manner that a harmonic component of the system clock falls outside carrier frequency bands of the satellite signals of the first and second satellites.
19. The receiver of claim 18 , wherein
the system clock is supplied to at least one of a baseband signal processing circuit or a logic circuit including a processor, an analog-digital converter configured to convert an analog signal into a digital signal, and a converter configured to convert a given direct-current voltage into another direct-current voltage.
20. The receiver of claim 19 , wherein
the first satellite is a GPS (Global Positioning System) or Galileo satellite, and
the second satellite is a GLONASS (GLObal NAvigation Satellite System) satellite.