Balancing amplitude and phase

• US 6,895,045 B2
• Filed: 04/15/2002
• Issued: 05/17/2005
• Est. Priority Date: 01/19/1999
• Status: Expired due to Fees

• Current Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Original Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Inventors: Dick, Stephen G., Kazakevich, Leonid, Özlütürk, Fatih M.
• Primary Examiner(s): PHU, PHUONG M
• Application Number:
  US10/122,992
• Publication Number:
  US 20020110201A1
• Time in Patent Office: 1,128 Days
• Field of Search: 375/235, 375/329, 375/322, 375/326, 375/327, 375/344, 375/346, 375/224, 375/278, 375/284, 375/340, 375/343, 375/285, 455/296, 455/312, 329/304
• US Class Current: 375/235
• CPC Class Codes: H04L 2027/0016 Stabilisation of local oscillators
• CPC Class Codes: H04L 2027/0024 at the receiver end
• CPC Class Codes: H04L 27/0014 Carrier regulation of chaotic carriers H04L27/001; for multicarrier receivers H04L27/2657
• CPC Class Codes: H04L 27/22 Demodulator circuits; Receiver circuits

Abstract

A system for balancing a signal having I and Q components includes means for cross correlating the I and Q components to produce a cross correlation product; means for adjusting the gain of each I and Q signal component in accordance with said cross correlation product; and means for adding one component with the adjustable gain of the other component to produce a phase-balanced signal.

Claims

1. A system for balancing a signal having I and Q components comprising:

means for cross correlating a balanced I signal with a balanced Q signal to produce a cross correlation product, the balanced I signal, being derived from the I component and the balanced Q signal, being derived from the Q component;

means for time averaging the cross correlation product;

means for adjusting a gain of each I and Q component in accordance with said time averaged cross correlation product; and

means for adding the I component with a Q component adjusted by said adjusting means, and the Q component with an I component adjusted by said adjusting means to produce a phase-balanced signal.

2. A system for balancing a signal having I and Q components, the system comprising:

means for comparing the magnitudes of an amplitude-balanced I signal with an amplitude-balanced Q signal, the amplitude-balanced I signal being derived from the I component and the amplitude-balanced Q signal being derived from the Q component;

means for generating a correction signal for both the I and Q components based on the magnitude comparison;

first means for adjusting a gain of the I and Q components in dependence upon said correction signal to produce an amplitude balanced signal;

means for cross correlating a phase-balanced I signal with a phase-balanced Q signal to derive a cross correlation product, the phase-balanced I signal and the phase-balanced Q signal being derived from the amplitude balanced signal;

means for time-averaging the correlation product;

second means for adjusting the gain of each I and Q component in accordance with said time-averaged cross correlation product; and

an adder for adding the I component with an adjusted Q component adjusted by the second means for adjusting, and the Q component with an adjusted I component adjusted by the second means for adjusting to produce an amplitude and phase balanced signal.

3. The system of claim 2, whereby said first means for adjusting includes I and Q amplifiers, and wherein said system further comprises:

respective I and Q low pass filters coupled to said means for comparing; and

an absolute value processor, having an input coupled to said low pass filters and an output coupled to said first means for adjusting.

4. A system for balancing a signal having I and Q components, comprising:

an I adjustable gain amplifiers;

a Q adjustable gain amplifier;

an I mixer, having a first mixer input for receiving an I input and a second mixer input coupled to an output of the Q adjustable gain amplifier, and having an I mixer output;

a Q mixer having a first mixer input for receiving a Q input and a second mixer input coupled to an output of the I adjustable gain amplifier, and having a Q mixer output; and

means for controlling a gain of each of said I adjustable gain amplifier and Q adjustable gain amplifier,

wherein the controlling means includes

an I and Q cross correlation means, coupled to said I and Q mixer outputs, which generates a cross correlation product; and

means for time-averaging the cross correlation product,

whereby said cross correlation product is coupled to said I adjustable gain amplifier and Q adjustable gain amplifier to control the gain of said I adjustable gain amplifier and Q adjustable gain amplifier; and

whereby phase balanced I and Q signals are output from said I mixer output and Q mixer output, respectively.

5. A system for balancing I and Q signal inputs, comprising:

an I adjustable gain amplifier for receiving said I signal input and having an I output;

a Q adjustable gain amplifier for receiving said Q signal input and having a Q output;

an I mixer having a first mixer input coupled to said I signal input and a second mixer input coupled to said Q output, and having an I mixer output;

a Q mixer having a first mixer input coupled to said Q signal input, and a second mixer input coupled to said I output and having a Q mixer output; and

means for controlling gain of each said I adjustable gain amplifier and Q adjustable gain amplifier,

wherein said controlling means comprises;

an I and Q cross correlation means coupled to said I and Q mixer outputs for generating a cross correlation product;

means for time averaging the cross correlation product;

said cross correlation product coupled to said I adjustable gain amplifier and Q adjustable gain amplifier to control gain of said I adjustable gain amplifier and Q adjustable gain amplifier; and

whereby phase balanced I and Q signals are output from said I mixer output and said Q mixer output, respectively.

6. A system for balancing a signal having I and Q components, comprising:

means for comparing the magnitude of the I component with the magnitude of the Q component;

means for generating a correction signal for both the I and Q components based on the magnitude comparison;

first means for adjusting a gain of the I and Q components in dependence upon said correction signal to produce an amplitude balanced signal;

means for cross correlating the I and Q components of an amplitude and phase balanced signal to derive a cross correlation product, the amplitude and phase balanced signal being derived from said amplitude balanced signal;

means for time averaging the cross correlation product;

second means for adjusting a gain of each amplitude balanced I and Q components in accordance with said time-averaged cross correlation product; and

means for adding the amplitude balanced I component with a Q component adjusted by the second adjusting means, and adding the amplitude balanced Q component with an I component adjusted by the second adjusting means to produce an amplitude and phase balanced signal.

7. A system for balancing a signal having I and Q components, comprising:

means for cross correlating a balanced I signal with a balanced Q signal, the balanced I signal, being derived from the I component and the balanced Q signal, being derived from the Q component;

means for deriving a cross correlation product;

means for time-averaging the cross correlation product;

means for adjusting a gain of each I and Q component in accordance with said time-averaged cross correlation product; and

means for adding the I component with a Q component adjusted by said adjusting means and the Q component with an I component adjusted by said adjusting means to produce a phase balanced signal.