TWO-STEP CHANNEL SELECTION FOR WIRELESS TRANSMITTER FRONT-ENDS

• US 20080318534A1
• Filed: 09/03/2008
• Published: 12/25/2008
• Est. Priority Date: 08/26/2005
• Status: Active Grant

• Current Assignee: University of Macau
• Original Assignee: University of Macau
• Inventors: U, Seng-Pan, MAK, Pui-In, MARTINS, Rui Paulo da Silva
• Granted Patent: US 8,019,290 B2
• Time in Patent Office: Days
• US Class Current: 455/91
• CPC Class Codes: H03D 3/007 by converting the oscillations into two quadrature related signals H03D3/245 takes precedence
• CPC Class Codes: H03H 11/1291 Current or voltage controlled filters
• CPC Class Codes: H04B 1/28 the receiver comprising at least one semiconductor device having three or more electrodes

Abstract

A reconfigurable multimode transmitter is disclosed, operating in accordance with a two-step channel selection. The first step provides for a fine channel selection and upconversion of a desired channel to either positive or negative IF. The second step is a coarse channel selection and upconversion of a desired channel to the RF. The receiver and transmitter can be used in a transceiver.

Claims

1. A reconfigurable transmitter capable of operating in a direct-up mode or a two-step-up mode, wherein in the direct-up mode the intermediate frequency IF=0, the transmitter comprising:

a baseband to intermediate frequency upconverter to perform baseband to intermediate frequency upconversion of a signal to either a positive IF or negative IF in the two-step-up mode, the upconverter being-bypassed in the direct-up mode;

an intermediate frequency to radio frequency upconverter and a local oscillator to perform intermediate frequency to radio frequency upconversion; and

a frequency synthesizer having a step size larger than one channel spacing.

2. The transmitter of claim 1, wherein the frequency synthesizer has a number of locking positions inferior to a total number of channels that are being upconverted.

3. The transmitter of claim 1, wherein the local oscillator is provided with 0°

and 90°

phase shifts, to allow downconversion of the plurality of channels in two parallel paths having a 90°

phase difference.

4. The transmitter of claim 1, further comprising a channel selection filter, the channel selection filter having a first mode wherein a desired channel is selected at a positive intermediate frequency in the two-step-up mode, a second mode where the desired channel is selected at a negative intermediate frequency in the two-step-up mode, and a third mode where the desired channel is selected at baseband in the direct-up mode.

5. The transmitter of claim 1, wherein the local oscillator is provided with 0°

, 90°

, 180° and

270°

phase shifts, to allow upconversion of a desired channel to positive or negative intermediate frequency.

6. The transmitter of claim 1, further comprising an analog-to-digital converter located downstream of the oscillator.

7. The transmitter of claim 1 wherein, in the two-step-up mode, IF=(n+0.5)CS, CS being the channel spacing, n=0, 1, 2, 3 . . . .

8. The transmitter of claim 1, wherein the local oscillator is a digital clock generator, and wherein channel selection is performed inside the digital clock generator.

9. The transmitter of claim 1, further comprising an analog-to-digital converter located upstream of the oscillator.

10. The transmitter of claim 1, wherein the baseband to intermediate frequency upconverter is a double-quadrature sampling-mixer arrangement.

11. The transmitter of claim 1, wherein the frequency synthesizer comprises an integer-N phase locked loop (PLL) and frequency dividers for channel selection.