DIRECT CONVERSION RECEIVER ARCHITECTURE

• US 20080014895A1
• Filed: 09/27/2007
• Published: 01/17/2008
• Est. Priority Date: 02/16/2001
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Peterzell, Paul, Severson, Matthew, Sih, Gilbert, Kang, Inyup, Li, Tao, Raghupathy, Arun, Walker, Brett, Holenstein, Christian, Challa, Raghu
• Granted Patent: US 8,615,212 B2
• Time in Patent Office: Days
• US Class Current: 455/324
• CPC Class Codes: H03G 3/3068 Circuits generating control signals for both R.F. and I.F. stages
• CPC Class Codes: H03G 3/3078 Circuits generating control signals for digitally modulated signals
• CPC Class Codes: H03G 3/3089 Control of digital or coded signals

Abstract

A direct downconversion receiver architecture having a DC loop to remove DC offset from the signal components, a digital variable gain amplifier (DVGA) to provide a range of gains, an automatic gain control (AGC) loop to provide gain control for the DVGA and RF/analog circuitry, and a serial bus interface (SBI) unit to provide controls for the RF/analog circuitry via a serial bus. The DVGA may be advantageously designed and located as described herein. The operating mode of the VGA loop may be selected based on the operating mode of the DC loop, since these two loops interact with one another. The duration of time the DC loop is operated in an acquisition mode may be selected to be inversely proportional to the DC loop bandwidth in the acquisition mode. The controls for some or all of the RF/analog circuitry may be provided via the serial bus.

Claims

1. An RF module, adapted to operate with a baseband integrated circuit, the baseband integrated circuit comprising a digital variable gain amplifier amplifying according to a second gain value, an automatic gain control loop operative to provide a first gain value and the second gain value, the first and second gain values determined in accordance with a desired signal amplitude, the RF module comprising:

an analog variable gain amplifier having a signal input, a gain input, and a signal output, the signal input receiving a radio frequency (RF) signal and the gain input adapted to receive the first gain value; and

a downconverter having an input coupled to the signal output of the variable gain amplifier, directly downconverting the downconverter input from RF to baseband to produce a downconverted output.

2. The RF module of claim 1, further comprising a DC offset canceller coupled to the output of the downconverter.

3. The RF module of claim 1, further comprising an analog to digital converter coupled to the output of the downconverter.

4. A method, operable with a baseband integrated circuit, the baseband integrated circuit comprising a digital variable gain amplifier amplifying according to a second gain value, an automatic gain control loop operative to provide a first gain value and the second gain value, the first and second gain values determined in accordance with a desired signal amplitude, the method comprising:

amplifying a radio frequency (RF) signal according to the first gain value; and

directly downconverting the amplified RF signal from RF to baseband to produce a downconverted output.

5. An apparatus, adapted to operate with a baseband integrated circuit, the baseband integrated circuit comprising a digital variable gain amplifier amplifying according to a second gain value, an automatic gain control loop operative to provide a first gain value and the second gain value, the first and second gain values determined in accordance with a desired signal amplitude, the apparatus comprising:

means for amplifying a radio frequency (RF) signal according to the first gain value; and

means for directly downconverting the amplified RF signal from RF to baseband to produce a downconverted output.

6. An RF module, adapted to operate with a baseband integrated circuit, the baseband integrated circuit comprising a digital variable gain amplifier amplifying according to a second gain value, and a gain controller adapted to measure the output from the digital variable gain amplifier and to generate a first gain value and the second gain value, the RF module comprising:

an analog variable gain amplifier having a signal input, a gain input, and a signal output, the signal input receiving a radio frequency (RF) signal and the gain input adapted to receive the first gain value; and

a downconverter having an input coupled to the signal output of the variable gain amplifier, directly downconverting the downconverter input from RF to baseband to produce a downconverted output.

7. The RF module of claim 6, further comprising a DC offset canceller coupled to the output of the downconverter.

8. The RF module of claim 6, further comprising an analog to digital converter coupled to the output of the downconverter.

9. A method, operable with a baseband integrated circuit, the baseband integrated circuit comprising a digital variable gain amplifier amplifying according to a second gain value, and a gain controller adapted to measure the output from the digital variable gain amplifier and to generate a first gain value and the second gain value, the method comprising:

amplifying a radio frequency (RF) signal according to the first gain value; and

directly downconverting the amplified RF signal from RF to baseband to produce a downconverted output.

10. An apparatus, adapted to operate with a baseband integrated circuit, the baseband integrated circuit comprising a digital variable gain amplifier amplifying according to a second gain value, and a gain controller adapted to measure the output from the digital variable gain amplifier and to generate a first gain value and the second gain value, the apparatus comprising:

means for amplifying a radio frequency (RF) signal according to the first gain value; and

means for directly downconverting the amplified RF signal from RF to baseband to produce a downconverted output.

11. A baseband integrated circuit, adapted to operate with an RF module, the RF module comprising an analog variable gain amplifier amplifying a received radio frequency (RF) signal according to a first gain value, the amplifier output coupled to a downconverter directly downconverting a downconverter input from RF to baseband to produce a downconverted signal, the apparatus comprising:

a digital variable gain amplifier having an amplifier input adapted to couple with the downconverted signal, a gain input receiving a second gain value, and an amplifier output; and

an automatic gain control loop operative to provide the first gain value and the second gain value to produce the digital variable gain amplifier output at a desired signal amplitude.

12. The baseband integrated circuit of claim 11, further comprising a DC offset canceller coupled to the input of the digital variable gain amplifier.

13. The baseband integrated circuit of claim 11, further comprising an analog to digital converter coupled to the input of the digital variable gain amplifier.

14. A baseband integrated circuit, adapted to operate with an RF module, the RF module comprising an analog variable gain amplifier amplifying a received radio frequency (RF) signal according to a first gain value, the amplifier output coupled to a downconverter directly downconverting a downconverter input from RF to baseband to produce a downconverted signal, the apparatus comprising:

a digital variable gain amplifier having an amplifier input adapted to couple with the downconverted signal, a gain input receiving a second gain value, and an amplifier output; and

a gain controller adapted to measure the amplifier output from the digital variable gain amplifier and to generate the first and second gain values.

15. The baseband integrated circuit of claim 14, further comprising a DC offset canceller coupled to the input of the digital variable gain amplifier.

16. The baseband integrated circuit of claim 14, further comprising an analog to digital converter coupled to the input of the digital variable gain amplifier.