Digitally convertible radio

• US 7,206,355 B2
• Filed: 12/02/2002
• Issued: 04/17/2007
• Est. Priority Date: 12/02/2002
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Inventors: McGowan, Neil N., Da Silveira, Marthinus W., Parvan, Mihai, Conrod, Matthew
• Primary Examiner(s): Tran, Khai
• Assistant Examiner(s): Ettehadieh, Aslan
• Application Number:
  US10/307,624
• Publication Number:
  US 20040105509A1
• Time in Patent Office: 1,597 Days
• Field of Search: 455/501, 455/63.1, 455/114.2, 455/114.3, 375/296, 375/297, 332/107, 332/123, 332/159, 332/162
• US Class Current: 375/295
• CPC Class Codes: H03F 1/3241 using predistortion circuits H03F1/3211, H03F1/3217 take precedence
• CPC Class Codes: H03F 1/3247 using feedback acting on predistortion circuits H03F1/3264 takes precedence
• CPC Class Codes: H03F 1/3282 Acting on the phase and the amplitude of the input signal
• CPC Class Codes: H03F 1/34 Negative-feedback-circuit arrangements with or without positive feedback H03F1/02 - H03F1/30, H03F1/38 - H03F1/50, H03F3/50 take precedence ; for rejection of common mode signals H03F3/45479
• CPC Class Codes: H03F 2200/204 A hybrid coupler being used at the output of an amplifier circuit
• CPC Class Codes: H03F 2200/393 A measuring circuit being coupled to the output of an amplifier
• CPC Class Codes: H03F 2200/451 the amplifier being a radio frequency amplifier
• CPC Class Codes: H03F 3/24 of transmitter output stages
• CPC Class Codes: H03F 3/602 Combinations of several amplifiers
• CPC Class Codes: H04B 1/0483 Transmitters with multiple parallel paths
• CPC Class Codes: H04B 2001/0433 with linearisation using feedback

Abstract

A forward link transmitter in a sectored cell includes a baseband processor having traditional baseband signal digital processing circuitry in addition to including a digital hybrid matrix (vector and delay compensated transformation module) whose phase and amplitude (vector) and delay may be adjusted to compensate for downstream errors that are introduced and detected by a feedback circuit. Accordingly, the baseband processor, by monitoring an output of an analog hybrid matrix producing modulated and amplified radio frequency (RF) signals just prior to propagation from an antenna, can determine errors produced by the analog circuitry including the analog hybrid matrix and may compensate for the same by introducing an amplitude, phase and delay adjustment (in the digital domain) into output digital waveform signals to compensate for the error introduced downstream to the baseband processor.

Claims

1. A radio transmitter, comprising:

a baseband processor for processing digital signals transmitted and received over a wireless communication link, which baseband processor produces a plurality of digital waveform signals each representing a corresponding plurality of analog signals, wherein the baseband processor includes;

a first processing module for generating the plurality of digital waveform signals, wherein each of the plurality of digital waveform signals represents a corresponding analog signal that is to be transmitted within corresponding cell sectors of a cellular network cell;

a second processing module coupled to receive and transfer the plurality of digital waveform signals to produce a corresponding plurality of transformed digital waveform signals, each containing components of each of the plurality of digital waveform signals; and

a third processing module coupled to receive and adjust the transformed digital waveform signals to compensate for distortion and to adjust peak power to produce a plurality of transformed and adjusted digital waveform signals;

a digital-to-analog conversion module coupled to receive the plurality of transformed and adjusted digital waveform signals, the digital-to-analog conversion module for converting the plurality of transformed and adjusted digital waveform signals from a digital domain to an analog domain, the digital-to-analog conversion module for producing a plurality of transformed analog signals;

an up-conversion module for mixing a local oscillation signal with each of the plurality of transformed analog signals to up-convert each of the plurality of transformed analog signals from a baseband frequency to a radio frequency to produce a plurality of transformed and adjusted RF analog signals;

at least one power amplifier module coupled to receive the plurality of transformed and adjusted RF analog signals to produce a plurality of transformed and amplified RF analog signals wherein the plurality of transformed and amplified RF analog signals each contain analog components of each of the plurality of analog signals;

a hybrid matrix module coupled to receive the plurality of transformed and amplified RF analog signals, the hybrid matrix module for separating analog components of the plurality of analog signals found in each of the plurality of transformed and amplified RF analog signals to create a plurality of amplified RF analog signals; and

feedback circuitry coupled to receive the plurality of amplified RF analog signals, the feedback circuitry including an analog-to-digital conversion module, the feedback circuitry for producing digital waveform signals to the second processing module of the baseband processor.

2. The radio transmitter of claim 1 wherein the second processing module detects at least one vector and delay error in an output signal.

3. The radio transmitter of claim 2 wherein the second processing module compensates for at least one vector and delay error in an output signal.

4. The radio transmitter of claim 1 wherein the digital waveform signals comprises three digital waveform signals that represent three corresponding analog signals.

5. The radio transmitter of claim 4 wherein the hybrid matrix module comprises a hybrid matrix, which hybrid matrix includes at least three inputs for receiving the plurality of transformed and amplified RF analog signals with components of the plurality of analog signals, the hybrid matrix further including at least three outputs for producing the plurality of amplified RF analog signals.

6. The radio transmitter of claim 1 wherein the feedback circuitry includes a plurality of directional couplers, each directional coupler of the plurality of directional couplers attached to each output of the hybrid matrix module wherein the outputs of the hybrid matrix module are propagated from an antenna and are also conducted back to the baseband processor in a feedback loop.

7. The radio transmitter of claim 6 further comprising a six-way switch for selectively coupling signals back into the baseband processor by way of an analog-to-digital converter, which six-way switch is coupled to receive each of the plurality of amplified RF analog signals.