I/Q demodulator device with three power detectors and two A/D converters

• US 6,999,528 B2
• Filed: 09/05/2001
• Issued: 02/14/2006
• Est. Priority Date: 09/06/2000
• Status: Expired due to Fees

• Current Assignee: Sony Deutschland GmbH (Sony Group Corp.)
• Original Assignee: Sony Limited (Sony Group Corp.)
• Inventors: Abe, Masayoshi, Sasho, Noboru, Ratni, Mohamed, Brankovic, Veselin, Krupezevic, Dragan
• Primary Examiner(s): Chin, Stephen
• Assistant Examiner(s): File, Erin M.
• Application Number:
  US09/947,145
• Publication Number:
  US 20020044613A1
• Time in Patent Office: 1,623 Days
• Field of Search: 329/306, 329/304, 375/345, 375/329, 375/322, 375/279, 375/308, 455/205
• US Class Current: 375/329
• CPC Class Codes: H03D 1/2245 using two quadrature channels H03D1/2209 takes precedence
• CPC Class Codes: H03D 3/007 by converting the oscillations into two quadrature related signals H03D3/245 takes precedence
• CPC Class Codes: H03D 9/04 for angle-modulated oscillations
• CPC Class Codes: H04B 1/30 for homodyne or synchrodyne receivers demodulator circuits H03D1/22

Abstract

The present invention relates to a method and a device for the I/Q demodulation of modulated RF signals. The I/Q demodulator (60) has a first input for the RF signal (61) to be demodulated and a second input for a RF signal (62) originating from a local oscillator (20). The demodulator (60) combines the two RF signals (61,62) to generate three output signals supplied to three power detectors. In a combination unit (70) the three power signals of the power detectors are merged in two signal branches wherein after passing an A/D converting (72) and digital processing unit (73) one signal is the I component and the other one is the Q component of the received modulated RF signal (61).

Claims

1. I/Q demodulator having a first input for the RF signal (61) to be demodulated and a second input for a RF signal (62) originating from a local oscillator (20), the demodulator (60) combining the two RF signals (61,62) to generate three output signals for power detectors, characterized by an analog combination unit (70) for combining three power signals (P1, P2, P3) output of the power detectors to two signal branches (X1, X2) for further digital processing to obtain I/Q values characterized in that the combination unit (70) comprises a splitting unit (7) for splitting one of the power signals (P1) into two subbranches.

2. I/Q demodulator according to claim 1, characterized by means (8) for individually adjusting the power of the subbranches.

3. I/Q demodulator according to claim 1, characterized in that the analog combination unit comprises means (10) for adding DC values of the subbranches to respectively one of the remaining two power signals (P2, P3).

4. I/Q demodulator according to claim 1, characterized by two A/D converter (72) for the output signals of the combination unit (51).

5. I/Q demodulator according to claim 1, characterized in that the outputs of the A/D converter (72) are supplied to a digital processing unit (73).

6. I/Q demodulator according to claim 5, characterized in that the digital processing unit (73) is designed to calculate I/Q values of the modulated RF signal (61).

7. Mobile communication device, characterized in that it comprises an I/Q demodulator according claim 1.

8. Method of demodulating a modulated RE signal, characterized by the following steps:

generating three output signals for power detectors by combining a first RF signal (61) to be demodulated with a second RF signal (62) originating from a local oscillator (20), and

processing (70) to three power signals (P1, P2, P3) of the power detectors to two signal branches (X1, X2) in an analog manner, and

processing digitally the two signal branches (X1, X2) to detect the I/Q values of the first RE signal (61) characterized in that one of the three power signals is split (7) in two subbranches.

9. Method according to claim 8, characterized in that the power of the subbranches is controllably adjusted.

10. Method according to claim 9, characterized in that each subbranch is combined (10) with respectively one of the remaining two power signals.

11. Method according to claim 10, characterized in that each of the signals resulting from the combination of each subbranch with one of the remaining two power signals is supplied to an A/D converter (72).

12. Method according to claim 8, characterized in that the outputs of the A/D converter (72) are supplied to a digital processing unit (73).

13. Method according to claim 12, characterized in that the digital processing unit (73) calculates the I/Q values of the modulated RF signal (61).

14. An I/Q demodulator comprising a first input for a first RF signal to be demodulated, a second input for a second RF signal supplied from a local oscillator, power detectors for the first and second RF signals to generate three power output signals, an analog combination unit for combining said three power output signals generated by said power detectors to provide two signal branches for further digital processing to obtain I/Q values, said analog combination unit including a splitting unit for splitting one of said power output signals into two subbranches for further digital processing with the remaining power output signals.