Adaptive phase and amplitude linearization method and apparatus

• US 6,628,923 B1
• Filed: 05/03/2000
• Issued: 09/30/2003
• Est. Priority Date: 05/03/2000
• Status: Expired due to Term

• Current Assignee: WSOU Investments, LLC (WSOU Holdings, LLC)
• Original Assignee: Nokia Networks (Nokia Corporation)
• Inventors: Eriksson, Peter
• Primary Examiner(s): Trost, William
• Assistant Examiner(s): Le, Danh C
• Application Number:
  US09/563,513
• Time in Patent Office: 1,245 Days
• Field of Search: 455/67.1, 455/226.1, 455/62, 455/63, 455/33.1, 455/33.2, 455/33.3, 455/54.1, 455/42.1, 455/56.1, 455/57.1, 455/67.3, 324/605, 324/613, 324/76.23, 324/85
• US Class Current: 455/63.1
• CPC Class Codes: H03H 17/0294 Variable filters; Programmable filters

Abstract

A apparatus for computing coefficient values for configuring a digital filter for compensating for non-linearity of an RF/IF device. The apparatus includes a reference signal generator, connected to an input of the RF/IF device, for generating an input reference signal to the RF/IF device. A vector signal analyzer, connected to an output of the RF/IF device, analyzes a response signal from the RF/IF device and outputs digital in-phase and quadrature-phase (I/Q) signals. A processor, connected to an output of said vector signal analyzer, computes a difference between the input reference signal and the digital in-phase and quadrature-phase (I/Q) signals. The processor calculates the coefficient values for configuring the digital filter based on the computed difference. A memory device, connected to the digital filter, stores the calculated coefficient values for the digital filter.

Claims

1. An adaptive compensating device for compensating for non-linearity of one of a radio frequency and intermediate frequency device, the adaptive compensating device comprising:

an adjustable output digital filter providing as an output signal of said digital filter a signal to the one of a radio frequency and intermediate frequency device; and

a means for adjusting the output signal of said digital filter to compensate for non-linearity of the one of a radio frequency and intermediate frequency device by pre-distorting an input signal to received by the one of a radio frequency and intermediate frequency device according to a correction signal so that the one of a radio frequency and an intermediate frequency device outputs a signal that is substantially linear with respect to at least one of amplitude and phase of the input signal over a predetermined bandwidth, the correction signal being a static pre-calculated signal based on measured characteristics of the non-linearity of the one of the radio frequency and intermediate frequency device, the means for adjusting being preconfigured with the correction signal.

2. The device of claim 1, wherein said digital filter is a finite impulse response filter for compensating for amplitude ripple.

3. The device of claim 2, wherein said digital filter is an infinite impulse response filter for compensating for group delay.

4. The device of claim 1, wherein said digital filter is a complex filter for compensating for error vector magnitude.

5. The device of claim 1, wherein the adaptive compensating device comprises a memory device for storing coefficients for said digital filter for generating the correction signal.

6. The apparatus of claim 1, wherein said digital filter is formed as an Application Specific Integrated Circuit (ASIC) device.

7. The apparatus of claim 5, wherein said coefficients in said memory are calculated for said digital filter prior to installation of said digital filter and said memory in said apparatus.