TRANSCEIVER

• US 20080311860A1
• Filed: 06/08/2008
• Published: 12/18/2008
• Est. Priority Date: 06/15/2007
• Status: Active Grant

• Current Assignee: Renesas Electronics Corporation
• Original Assignee: Renesas Technology Corporation (Renesas Electronics Corporation)
• Inventors: Yamawaki, Taizo, Tanaka, Satoshi, Akamine, Yukinori, Maeda, Koji, Kamizuma, Hiroshi, Cha, Sungwoo
• Granted Patent: US 8,086,188 B2
• Time in Patent Office: Days
• US Class Current: 455/73
• CPC Class Codes: H04B 1/28 the receiver comprising at least one semiconductor device having three or more electrodes

Abstract

The transmitter of the transceiver includes: a transmitter-side mixers of a transmitter-side modulator; a transmitter-side voltage-controlled oscillator; and a transmitter-side divider. The divider having a dividing factor of a non-integral number is supplied with an oscillating output of the oscillator. A pair of non-quadrature local signals having a phase difference of 90° plus a predetermined offset angle is produced by the divider and supplied to the mixers. The transmitter includes a phase-shift unit which converts a pair of quadrature transmit signals having a phase difference of about 90° on an analog basis into a pair of non-quadrature shifted transmit signals. Consequently, quadrature modulation is performed by the mixers. Use of a similar configuration enables the reduction in interference of an RF signal with local signals supplied to receiver-side mixers of the receiver.

Claims

1. A transceiver comprising:

a receiver including a receiver-side demodulator for converting a received RF receive signal into an analog receive signal; and

a transmitter including a transmitter-side modulator for converting an analog transmit signal into an RF transmit signal,

wherein the transmitter further includes

a digital-to-analog converter for converting a digital transmit signal into the analog transmit signal,

a transmitter-side voltage-controlled oscillator, and

a transmitter-side divider for frequency-dividing a transmitter-side oscillating output signal produced by the transmitter-side voltage-controlled oscillator thereby to produce first and second transmitter-side local signals to be supplied to the transmitter-side modulator,

a dividing factor of the transmitter-side divider is set to a non-integral number larger than one,

the transmitter-side divider having the dividing factor set to the non-integral number is composed of a logic divider which performs a logic operation thereby to produce the first and second transmitter-side local signals differing in phase,

the first and second transmitter-side local signals produced by the transmitter-side divider make a pair of non-quadrature local signals having a phase difference of 900 plus a predetermined local offset angle,

the digital transmit signal consists of a pair of quadrature transmit signals having a phase difference of about 90°

on an analog basis,

the transmitter further includes a phase-shift unit for converting the pair of quadrature transmit signals into a pair of non-quadrature shifted transmit signals having a phase difference of 90°

plus a predetermined transmit signal offset angle on an analog basis,

mixing of the pair of non-quadrature shifted transmit signals from the phase-shift unit, and the pair of non-quadrature local signals from the transmitter-side divider is performed in the transmitter-side modulator of the transmitter, and

the RF transmit signal is formed by outputs of the transmitter-side modulator of the transmitter according to quadrature modulation as a result of the mixing.

2. The transceiver of claims 1, wherein the transmitter-side modulator includes a first mixer, a second mixer and an adder,

when the transmitter-side oscillating output signal produced by the transmitter-side voltage-controlled oscillator is supplied to the transmitter-side divider, the transmitter-side divider produces the first and second transmitter-side local signals to be supplied to the first and second mixers respectively,

an analog signal phase difference between first and second analog transmit signals to be supplied to the first and second mixers respectively as the pair of non-quadrature shifted transmit signals is 90°

plus a predetermined analog offset angle, and

the RF transmit signal is formed by an output of the adder connected to outputs of the first and second mixers of the transmitter-side modulator.

3. The transceiver of claim 2, wherein the digital transmit signal includes first and second digital transmit signals,

the first and second digital transmit signals are supplied to first and second input terminals of the phase-shift unit respectively,

the digital-to-analog converter includes

a first digital-to-analog converter supplied with a first digital shifted transmit signal from a first output terminal of the phase-shift unit, and

a second digital-to-analog converter supplied with second digital shifted transmit signal from a second output terminal of the phase-shift unit, and

the first digital shifted transmit signal from the first output terminal of the phase-shift unit, and the second digital shifted transmit signal from the second output terminal are set to have a phase difference of 90°

plus the predetermined transmit signal offset angle on an analog basis.

4. The transceiver of claim 2, wherein the digital transmit signal includes first and second digital transmit signals,

the digital-to-analog converter includes

a first digital-to-analog converter supplied with the first digital transmit signal, and

a second digital-to-analog converter supplied with the second digital transmit signal,

the first analog transmit signal from the first digital-to-analog converter, and the second analog transmit signal from the second digital-to-analog converter are supplied to first and second input terminals of the phase-shift unit respectively,

the first and second analog transmit signals to be supplied to the first and second mixers of the transmitter-side modulator respectively are produced from the first and second input terminals of the phase-shift unit and

the first analog transmit signal arising at the first output terminal of the phase-shift unit, and the second analog transmit signal arising at the second output terminal are set to have a phase difference of 90°

plus the predetermined transmit signal offset angle.

5. The transceiver of claim 2, wherein an oscillating frequency of the transmitter-side oscillating output signal produced by the transmitter-side voltage-controlled oscillator is controlled by a phase lock loop including, in its closed loop, the transmitter-side voltage-controlled oscillator, an oscillation divider, a phase comparator and a low-pass filter.

6. The transceiver of claim 5, wherein a sum of the predetermined local offset angle and predetermined transmit signal offset angle is substantially zero.

7. The transceiver of claim 5, wherein the transmitter-side modulator, transmitter-side voltage-controlled oscillator, and transmitter-side divider constitute a transmitter according to one of a direct up-conversion transmitter architecture and a low-IF up-conversion transmitter architecture.

8. The transceiver of claim 7, wherein the transmitter transmits the RF transmit signal having a frequency set within a range between about 1.7 and 2.0 GHz according to WCDMA system.

9. The transceiver of claim 2, wherein the receiver-side demodulator of the receiver, and the transmitter-side modulator, digital-to-analog converter, transmitter-side voltage-controlled oscillator, transmitter-side divider and phase-shift unit of the transmitter are arranged into a semiconductor chip.

10. The transceiver of claim 2, wherein the non-integral number of the dividing factor of the transmitter-side divider is set to a ratio of an odd number and an even number, or a ratio of different odd numbers.

11. A transceiver comprising:

a receiver including a receiver-side demodulator for converting a received RF receive signal into an analog receive signal; and

a transmitter including a transmitter-side modulator for converting an analog transmit signal into an RF transmit signal,

wherein the receiver further includes

a low-noise amplifier for amplifying the RF receive signal,

a receiver-side voltage-controlled oscillator,

a receiver-side divider for frequency-dividing a receiver-side oscillating output signal produced by the receiver-side voltage-controlled oscillator thereby to produce first and second receiver-side local signals to be supplied to the receiver-side demodulator, and

an analog-to-digital converter for converting an analog receive signal produced in the receiver-side demodulator and output through an output thereof into a digital receive signal,

a dividing factor of the receiver-side divider is set to a non-integral number larger than one,

the receiver-side divider having the dividing factor set to the non-integral number is composed of a logic divider which performs a logic operation thereby to produce the first and second receiver-side local signals differing in phase,

the first and second receiver-side local signals produced by the receiver-side divider make a pair of non-quadrature local signals having a phase difference of 90°

plus a predetermined local offset angle,

mixing of an RF amplified receive signal from the low-noise amplifier and the pair of non-quadrature local signals from the receiver-side divider is performed in the receiver-side demodulator of the receiver,

the analog receive signal is formed by outputs of the receiver-side demodulator of the receiver according to non-quadrature demodulation as a result of the mixing,

the analog receive signal consists of a pair of non-quadrature receive signals having a phase difference of 90°

plus a predetermined receive signal offset angle, and

the receiver further includes a phase-shift unit for converting the pair of non-quadrature receive signals into a pair of quadrature shifted receive signals having a phase difference of about 90°

on an analog basis.

12. The transceiver of claim 11, wherein the receiver-side demodulator includes a first mixer and a second mixer,

when the receiver-side oscillating output signal produced by the receiver-side voltage-controlled oscillator is supplied to the receiver-side divider, the receiver-side divider produces the first and second receiver-side local signals to be supplied to the first and second mixers respectively,

the pair of non-quadrature receive signals is formed as the analog receive signal by outputs of the first and second mixers of the transmitter-side modulator supplied with the RF amplified receive signal from the low-noise amplifier.

13. The transceiver of claim 12, wherein the pair of non-quadrature receive signals as the analog receive signal includes first and second analog receive signals,

the analog-to-digital converter includes a first analog-to-digital converter supplied with the first analog receive signal, and a second analog-to-digital converter supplied with the second analog receive signal,

a first digital receive signal from an output of the first analog-to-digital converter, and a second digital receive signal from an output of the second analog-to-digital converter are supplied to first and second input terminals of the phase-shift unit respectively,

the first and second digital receive signals from the analog-to-digital converter have a phase difference of 90°

plus an offset angle substantially equal to the predetermined receive signal offset angle on an analog basis, and

first and second shifted digital receive signals produced in the phase-shift unit and respectively output through first and second output terminals thereof are set to have a phase difference of about 90°

on an analog basis.

14. The transceiver of claim 12, wherein the pair of non-quadrature receive signals as the analog receive signal includes first and second analog receive signals,

the first and second analog receive signals are supplied to first and second input terminals of the phase-shift unit,

the analog-to-digital converter includes a first analog-to-digital converter supplied with a first shifted analog receive signal from a first output terminal of the phase-shift unit, and a second analog-to-digital converter supplied with a second shifted analog receive signal from a second output terminal of the phase-shift unit,

the first and second shifted analog receive signals produced in the phase-shift unit and respectively output through the first and second output terminals thereof are set to have a phase difference of about 90°

, and

a first shifted digital receive signal produced by the first analog-to-digital converter, and a second shifted digital receive signal produced by the second analog-to-digital converter are set to have a phase difference of about 90°

on an analog basis.

15. The transceiver of claim 12, wherein an oscillating frequency of the receiver-side oscillating output signal produced by the receiver-side voltage-controlled oscillator is controlled by a phase lock loop including, in its closed loop, the receiver-side voltage-controlled oscillator, an oscillation divider, a phase comparator and a low-pass filter.

16. The transceiver of claim 15, wherein the receiver-side demodulator, receiver-side voltage-controlled oscillator and receiver-side divider constitute a receiver according to one of a direct down-conversion receiver architecture, a low-IF down-conversion receiver architecture and a digital IF down-conversion receiver architecture.

17. The transceiver of claim 16, wherein the receiver receives a WCDMA system RF receive signal with a frequency set between about 1.8 and 2.17 GHz.

18. The transceiver of claim 12, wherein the receiver-side demodulator, low-noise amplifier, receiver-side voltage-controlled oscillator, transmitter-side divider, analog-to-digital converter and phase-shift unit of the receiver, and the transmitter-side modulator of the transmitter are arranged into a semiconductor chip.

19. The transceiver of claim 12, wherein the non-integral number of the dividing factor of the receiver-side divider is set to a ratio of an odd number and an even number, or a ratio of different odd numbers.