Modulation method for improving signal conversion gain and high-gain modulator thereof

Patent metadata

Field	Value
Publication number	US-9319076-B2
Application number	US-201414559159-A
Country	US
Kind code	B2
Filing date	Dec 3, 2014
Priority date	Apr 30, 2014
Publication date	Apr 19, 2016
Grant date	Apr 19, 2016

Abstract

A modulation method includes sampling the first input signal by using the first local oscillation signal and the second local oscillation signal to generate the first sampled signal, sampling the second input signal by using the third local oscillation signal and the fourth local oscillation signal to generate the second sampled signal, sampling the second input signal by using the first local oscillation signal and the second local oscillation signal to generate the third sampled signal, sampling the first input signal by using the third local oscillation signal and the fourth local oscillation signal to generate the fourth sampled signal, adding the first sampled signal and the second sampled signal to produce the first modulation signal, adding the third sampled signal and the fourth sampled signal to generate the second modulation signal, and adding the first modulation signal and the second modulation signal to generate an output signal.

First claim

What is claimed is:

1. A modulation method for improving signal conversion gain, comprising:
sampling a first input signal by using a first local oscillation signal and a second local oscillation signal to generate a first sampled signal;
sampling a second input signal by using a third local oscillation signal and a fourth local oscillation signal to generate a second sampled signal, wherein the first input signal and the second input signal have a phase difference, and the first local oscillation signal, the second local oscillation signal, the third local oscillation signal, and the fourth local oscillation signal have different phases;
sampling the second input signal by using the first local oscillation signal and the second local oscillation signal to generate a third sampled signal;
sampling the first input signal by using the third local oscillation signal and the fourth local oscillation signal to generate a fourth sampled signal;
adding the first sampled signal and the second sampled signal to generate a first modulation signal;
adding the third sampled signal and the fourth sampled signal to generate a second modulation signal; and
adding the first modulation signal and the second modulation signal to generate an output signal.

2. The modulation method according to claim 1 , wherein the phase difference is 90 degrees.

3. The modulation method according to claim 1 , wherein a phase difference between the first local oscillation signal and the third local oscillation signal, between the third local oscillation signal and the second local oscillation signal, and between the second local oscillation signal and the fourth local oscillation signal ranges from 80 degrees to 100 degrees.

4. The modulation method according to claim 1 , further comprising:
generating the first local oscillation signal, the second local oscillation signal, the third local oscillation signal, and the fourth oscillation local signal by a local oscillation unit.

5. The modulation method according to claim 4 , wherein a duty cycle of the first local oscillation signal, the second local oscillation signal, the third local oscillation signal, and the fourth oscillation local signal is less than 35%.

6. The modulation method according to claim 1 , wherein the sampling step is performed by a mixer.

7. A high-gain modulator, comprising:
a first modulation unit that modulates an input signal by using a first local oscillation signal, a second local oscillation signal, a third local oscillation signal, and a fourth local oscillation signal to generate a first modulation signal, wherein the first local oscillation signal, the second local oscillation signal, the third local oscillation signal, and the fourth local oscillation signal have different phases;
a second modulation unit that modulates the input signal by using the first local oscillation signal, the second local oscillation signal, the third local oscillation signal, and the fourth local oscillation signal to generate a second modulation signal, wherein the first modulation signal and the second modulation signal have a phase difference; and
an adder circuit that adds the first modulation signal and the second modulation signal to generate an output signal.

8. The modulator according to claim 7 , wherein a phase difference between the first local oscillation signal and the third local oscillation signal, between the third local oscillation signal and the second local oscillation signal, and between the second local oscillation signal and the fourth local oscillation signal ranges from 80 degrees to 100 degrees.

9. The modulator according to claim 8 , wherein the input signal comprises an in-phase signal and a quadrature signal.

10. The modulator according to claim 7 , further comprising:
a local oscillation unit, used to generate the first local oscillation signal, the second local oscillation signal, the third local oscillation signal, and the fourth local oscillation signal.

11. The modulator according to claim 10 , wherein the local oscillation unit comprises:
a local oscillator that generates an oscillation signal;
a frequency divider that divides the oscillation signal to generate a plurality of quad-phase output signals; and
a duty cycle generator that converts a duty cycle of the plurality of quad-phase output signals into a duty cycle required by the primary local oscillation signal, so as to output the first local oscillation signal, the second local oscillation signal, the third local oscillation signal, and the fourth local oscillation signal.

12. The modulator according to claim 11 , wherein the duty cycle required by the first local oscillation signal, the second local oscillation signal, the third local oscillation signal, and the fourth local oscillation signal is less than 35%.

13. The modulator according to claim 7 , wherein the input signal comprises an in-phase signal and a quadrature signal, the first modulation unit further comprises:
a first mixer, for sampling the in-phase signal by using the first local oscillation signal and the second local oscillation signal to generate a first sampled signal;
a second mixer, for sampling the quadrature signal by using the third local oscillation signal and the fourth local oscillation signal to generate a second sampled signal; and
a first adder, for adding the first sampled signal and the second sampled signal to generate the first modulation signal.

14. The modulator according to claim 13 , wherein the second modulation unit further comprises:
a third mixer, for sampling the quadrature signal by using the first local oscillation signal and the second local oscillation signal to generate a third sampled signal;
a fourth mixer, for sampling the in-phase signal by using the third local oscillation signal and the fourth local oscillation signal to generate a fourth sampled signal; and
a second adder, for adding the third sampled signal and the fourth sampled signal to generate the second modulation signal.

15. A modulation method, comprising:
based on a duty cycle of a given signal, sampling an in-phase signal in a first timeslot and a second timeslot in each cycle of the given signal, to generate a first sampled signal;
based on the duty cycle of the given signal, sampling a quadrature signal in a third timeslot and a fourth timeslot in each cycle of the given signal, to generate a second sampled signal;
based on the duty cycle of the given signal, sampling the quadrature signal in the first timeslot and the second timeslot in each cycle of the given signal, to generate a third sampled signal;
based on the duty cycle of the given signal, sampling the in-phase signal in the third timeslot and the fourth timeslot in each cycle of the given signal, to generate a fourth sampled signal, wherein a time difference exists between the first timeslot and the third timeslot, between the third timeslot and the second timeslot, and between the second timeslot and the fourth timeslot; and
combining the first sampled signal, the second sampled signal, the third sampled signal, and the fourth sampled signal to form an output signal.

16. The modulation method according to claim 15 , wherein a width of the timeslots is one-fourth of the cycle of the given signal.

17. The modulation method according to claim 16 , wherein the duty cycle of the given signal is less than 35%.

18. The modulation method according to claim 17 , wherein the sampling action is performed by a mixer.

Assignees

• Univ Nat Taiwan

Inventors

• Chen Yi-Jan
• Tsai Li-Fan

Classifications

• H04B1/04 Primary

  Circuits · CPC title

• H03C3/00 Primary

  Angle modulation (H03C5/00, H03C7/00 take precedence) · CPC title

• H03D7/1466

  Passive mixer arrangements · CPC title

• H03D7/1458

  Double balanced arrangements, i.e. where both input signals are differential · CPC title

• H03D7/1441

  using field-effect transistors (H03D7/145 takes precedence) · CPC title