Calibration of a N-port receiver

• US 6,735,261 B1
• Filed: 07/07/2000
• Issued: 05/11/2004
• Est. Priority Date: 07/08/1999
• Status: Expired due to Fees

• Current Assignee: Sony Corporation (Sony Group Corp.), Sony International Europe Gmbh (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.), Sony International Europe Gmbh (Sony Group Corp.)
• Inventors: Krupzevic, Dragan, Oberschmidt, Gerald, Abe, Masayoshi, Dölle, Thomas, Konschak, Tino, Brankovic, Veselin
• Primary Examiner(s): Bocure, Tesfaldet
• Assistant Examiner(s): GHULAMALI, QUTBUDDIN
• Application Number:
  US09/611,488
• Time in Patent Office: 1,404 Days
• Field of Search: 375/316, 375/224, 375/226, 375/345, 375/371, 375/373, 332/103
• US Class Current: 375/316
• 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
• CPC Class Codes: H04L 27/2331 wherein the received signal is demodulated using one or more delayed versions of itself

Abstract

A technique for calibrating a N-port receiver, such as for example a 5- or 6-port receiver is proposed. The N-port receiver (1) comprises a first input (2) for a RF signal to be detected, a second input (3) for a RF signal originating from a local oscillator (4) and N−2 output terminals. Calibrating signals are generated on the basis of the RF signal supplied by the local oscillator (4). The calibration signals are fed to the first input (2) and/or the second input (3) of the N-port receiver (1). Calibration coefficients are calculated on the basis of the output signals generated by the N-port receiver (1) in response to the feeding of the calibration signals. The calibration signals are unmodulated signals and are only processed by means of a passive RF circuitry in the calibration device (100).

The solutions according to the present invention allow a simple calibration of N-port receivers, which can be used as IQ demodulators or converters. Thereby a local oscillator (4) is used as a RF source for the calibration.

Claims

1. Method for calibrating a N-port receiver, wherein the N-port receiver (1) has two inputs and N−

2 outputs;

the two inputs consisting of a first input (2) for a RF signal to be detected and a second input (2) for a RF signal originating from a local oscillator (4);

N being an integer larger than 2, the method comprising the following steps;

generating calibration signals using the local oscillator signal (4),

feeding the calibration signals to one of the first input (2) and the second input (3) of the N-port receiver (1), and

calculating calibration coefficients on the basis of the output signals of the N-port receiver (1) in response to the feeding of the calibration signals, wherein the calibration signals are unmodulated signals.

2. Method according to claim 1, characterized in that the step of generating calibration signals comprises the following steps:

dividing the local oscillator signal into a first and a second branch, and

processing at least one of the first and second branch.

3. Method according to claim 2, characterized in that the step of processing at least one of the first and second branch comprises the following step:

generating a plurality of RF signals relatively phase shifted to each other, and

supplying sequentially the RF signals relatively phase shifted to each other to the first input (2) and/or the second input (3) of the N-port receiver (1).

4. Method according to claim 1, characterized in that the step of calculating calibration coefficients comprises the steps of:

sampling time sequentially a plurality of output signals generated by the N-port receiver (1) in response to the feeding of the calibration signal, wherein the calibration signal assumes different phase states, and

calculating the elements of a calibration matrix as calibration coefficients.

5. Method according to claim 1, characterized in that the calibration is performed off-line.

6. Method according to claim 5, characterized in that the calibration is performed once after manufacturing of the N-port receiver (1).

7. Method according to claim 1, characterized in that the calibration is performed on-line.

8. Method according to claim 1, characterized in that it comprises furthermore the step of storing (16) the calculated calibration coefficients.

9. Method according to claim 1, characterized in that the calibration signal sequentially in time assumes at least four different complex states.

10. Method according to claim 1, characterized in that the first input (2) is isolated from the second input (3) of the N-port receiver (1).

11. Method according to claim 1, characterized in that the calibration signals are generated by passing the local oscillator signal through a passive circuitry (100).

12. Method according to claim 1, characterized in that the calibration coefficients are calculated by averaging over a plurality of calibration cycles.

13. Calibration device for a N-port receiver, wherein the N-port receiver (1) has two inputs and N−

2 outputs;

the two inputs consisting of a first input (2) for a RF signal to be detected and a second input (2) for a RF signal originating from a local oscillator (4);

N being an integer larger than 2, the calibration device comprising;

means (100) for generating calibration signals on the basis of the RF signal supplied by the local oscillator (4),

means for feeding the calibration signals to one of the first input (2) and the second input (3) of the N-port receiver (1), and

means for calculating calibration coefficients on the basis of the output signals generated by the N-port receiver (1) in response to the feeding of the calibration signals, wherein the calibration signals are unmodulated signals.

14. Device according to claim 13, characterized in that the means (100) for generating the calibration signals on the basis of the RF signal supplied by the local oscillator (4) is a passive circuitry.

15. Device according to claim 13, characterized in that the means for generating calibration signals comprises:

a power divider for dividing the RF signal supplied by the local oscillator (4) into a first and a second branch, and

means for processing at least one of the first and second branch.

16. Device according to claim 15, characterized in that the means for processing at least one of the first and second branch comprise:

phase shifting means for generating a plurality of RF signals relatively phase shifted to each other, and

means for supplying sequentially the RF signals relatively phase shifted to each other to the first input (2) and/or second input (3) of the N-port receiver (1).

17. Device according to claim 13, characterized in that the means for calculating calibration coefficients comprise:

means for sampling time sequentially a plurality of output signals generated by the N-port receiver (1) in response to the feeding of the calibration signal, wherein the calibration signal assumes different phase states, and

means for calculating the elements of a calibration matrix as calibration coefficients.

18. Device according to claim 13, characterized in that it comprises furthermore a memory (16) for storing the calculated calibration coefficients.

19. Device according to claim 13, characterized in that the calibration signal sequentially in time assumes at least four different complex states.

20. Device according to claim 13, characterized in that the first input (2) is isolated from the second input (3) of the N-port receiver (1) by means of a isolation block (13) with an active circuitry.

21. N-port receiver for modulated RF signals, characterized in that it comprises a calibration device according to claim 13.

22. N-port receiver according to claim 21, the calibration device (100) and the N-port receiver (1) are integrated on one chip.