Single local oscillator architecture for dual-band microwave/millimeter-wave transceiver
Systems for a dual-band transceiver that re-uses a lower frequency transmitter to drive a local oscillator (LO) for high frequency circuits are disclosed herein. The need for a LO lineup requiring high frequency and high power is eliminated. The output of a lower frequency band is modified to be used as a LO drive for the higher frequency band transceiver. Using a carrier recovery loop, the system is operable to simultaneously operate in both bands. The result is a solution that eliminate the design of a high performance LO circuits for a higher band of a mmW dual-band system. This significantly reduces the overall complexity of the system. Furthermore, the inventive architecture reduces the design complexity and overall cost to implement dual-band circuit.
1. A bi-directional dual-band transceiver, comprising:
a baseband circuit producing a modulated signal and a continuous wave (CW) tone;
a first transceiver circuit comprising:
a first mixer coupled to the baseband circuit and driven by a local oscillator to selectively up-convert from and down-convert to the CW tone; and
a first amplification module comprising a first amplifier and a second amplifier, wherein a first switch is used to selectively couple the first amplifier to the first mixer and an antenna, and a second switch is used to selectively couple the second amplifier to the first mixer and the antenna; and
a second transceiver circuit comprising:
a second mixer coupled to the baseband circuit and operable to selectively down-convert to and up-convert from the modulated signal;
a third switch to selectively couple the first amplification module and the second mixer; and
a second amplification module comprising a third amplifier and a fourth amplifier, wherein a fourth switch is used to selectively couple the third amplifier to the second mixer and the antenna, and a fifth switch is used to selectively couple the fourth amplifier to the second mixer and the antenna.
2. The transceiver of claim 1 , wherein the first, second, fourth, and fifth switches are double-pole double-throw switches and the third switch is a single-throw switch.
3. The transceiver of claim 1 , further comprising a passive frequency multiplier coupled between the third switch and a local oscillator filter, wherein the local oscillator filter is coupled to the passive frequency multiplier and the second mixer and operable to drive the second mixer, and wherein the third switch open causes operation in a first band mode, and the third switch closed causes operation in a second band mode in which a signal generated by the first amplifier is used to drive the second mixer.
4. The transceiver of claim 3 , wherein the first, second, fourth, and fifth switches are selectively toggled causing selective receive mode and transmit mode operation.
5. The transceiver of claim 3 , further comprising a directional coupler coupled to a carrier recovery loop which is coupled between the first amplification module and the passive frequency multiplier, wherein the directional coupler and the carrier recovery loop are operable to recover a modulated local multipoint distribution service (LMDS) signal back to a carrier CW signal when the operation is in the second band mode.
6. The transceiver of claim 5 , further comprising a third mixer coupled to the baseband circuit and a sixth switch, wherein the sixth switch selectively couples the first amplification module to one of the first mixer and the third mixer.
7. The transceiver of claim 6 , wherein the third mixer is operable in receive mode to generate a second CW tone for down-converting as a second local oscillator.
8. The transceiver of claim 7 , wherein the first or fourth switch closed causes operation in a transmit mode, and the second or fifth switch closed causes operation in a receive mode.
9. The transceiver of claim 3 , wherein the passive frequency multiplier is operable to generate a millimeter wave (mmW) output frequency.
10. The transceiver of claim 3 , wherein the local oscillator filter is operable to filter spurious emissions.
11. The transceiver of claim 1 , further comprising an intermediate frequency local oscillator operable to drive a third mixer, wherein the third mixer is coupled between the baseband circuit and the second mixer and is operable to up or down convert the modulated signal to or from, respectively, an intermediate frequency between 12.5 and 22.5 GHz, and wherein further the first transceiver circuit is a V-band circuit and the first mixer is a V-band mixer.
12. The transceiver of claim 11 , wherein the third switch open causes operation in a first band mode, and the third switch closed causes operation in a second band mode in which a signal generated by the first amplifier is operable to drive the second mixer.
13. The transceiver of claim 1 , wherein the first amplification module is a local multipoint distribution service (LMDS) receiver circuit, the first mixer is an LMDS band mixer, the second amplification module is an E-band receiver circuit, and the second mixer is an E-band mixer.
14. The transceiver of claim 1 , wherein the antenna is a dual-band antenna.
15. The transceiver of claim 1 , wherein the first and third amplifiers are power amplifiers, and wherein the second and fourth amplifiers are low noise amplifiers.
16. A bi-directional dual-band transceiver, comprising:
a baseband circuit producing a modulated signal and a continuous wave (CW) tone;
a first transceiver circuit comprising:
a first mixer coupled to the baseband circuit and driven by a local oscillator to selectively up-convert from and down-convert to the CW tone; and
a first amplifier;
a first switch to selectively couple the first amplifier to the first mixer and an antenna;
a second amplifier; and
a second switch to selectively couple the second amplifier to the first mixer and the antenna;
a second transceiver circuit comprising:
a second mixer coupled to the baseband circuit and operable to selectively down-convert to and up-convert from the modulated signal;
a third switch to selectively couple the first amplification module and the second mixer;
a third amplifier;
a fourth switch to selectively couple the third amplifier to the second mixer and the antenna;
a fourth amplifier; and
a fifth switch to selectively couple the fourth amplifier to the second mixer and the antenna;
an intermediate frequency local oscillator operable to drive a third mixer; and
the third mixer coupled between the baseband circuit and the second mixer, and operable to up or down convert the modulated signal to or from, respectively, an intermediate frequency.
17. The bi-directional dual-band transceiver of claim 16 , wherein the third switch open causes operation in a first band mode, and the third switch closed causes operation in a second band mode in which a signal generated by the first amplifier is operable to drive the second mixer.
18. A bi-directional dual-band transceiver, comprising:
a baseband circuit producing a modulated signal and a continuous wave (CW) tone;
a first transceiver circuit comprising:
a first mixer coupled to the baseband circuit and driven by a local oscillator to selectively up-convert from and down-convert to the CW tone; and
a first amplifier;
a first switch to selectively couple the first amplifier to the first mixer and an antenna;
a second amplifier; and
a second switch to selectively couple the second amplifier to the first mixer and the antenna;
a second transceiver circuit comprising:
a second mixer coupled to the baseband circuit and operable to selectively down-convert to and up-convert from the modulated signal;
a third switch to selectively couple the first amplification module and the second mixer;
a third amplifier;
a fourth switch to selectively couple the third amplifier to the second mixer and the antenna;
a fourth amplifier; and
a fifth switch to selectively couple the fourth amplifier to the second mixer and the antenna;
a passive frequency multiplier coupled between the third switch and a local oscillator filter; and
the local oscillator filter, coupled to and operable to drive the second mixer.
19. The bi-directional dual-band transceiver of claim 18 , wherein the first, second, fourth, and fifth switches are double-pole double-throw switches, and the third switch is a single-throw switch.