Dual band architectures for mobile stations

• US 6,215,988 B1
• Filed: 05/27/1999
• Issued: 04/10/2001
• Est. Priority Date: 05/15/1997
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Nokia Mobile Phones UK Limited (Nokia Corporation)
• Inventors: Matero, Jorma
• Primary Examiner(s): Nguyen, Lee
• Application Number:
  US09/321,032
• Time in Patent Office: 684 Days
• Field of Search: 455/575, 455/552, 455/553, 455/84, 455/85, 455/86, 455/76, 455/550, 455/188.1, 455/180.1, 455/180.2, 455/185.2, 455/102, 455/112, 455/118, 455/207, 455/209, 455/314
• US Class Current: 455/188.1
• CPC Class Codes: H04B 1/005 adapting radio receivers, transmitters andtransceivers for operation on two or more bands, i.e. frequency ranges
• CPC Class Codes: H04B 1/0057 using diplexing or multiplexing filters for selecting the desired band
• CPC Class Codes: H04B 1/006 using switches for selecting the desired band H04B1/0057 takes precedence
• CPC Class Codes: H04B 1/0096 where a full band is frequency converted into another full band
• CPC Class Codes: H04B 1/406 with more than one transmission mode, e.g. analog and digital modes
• CPC Class Codes: H04B 1/408 the transmitter oscillator frequency being identical to the receiver local oscillator frequency
• CPC Class Codes: H04B 1/56 with provision for simultaneous communication in two directions

Abstract

A dual band user terminal (10) includes a controller (18) for outputting a BAND signal for specifying operation in one of a first frequency band or a second, higher frequency band; a single frequency synthesizer (46) that is responsive to the BAND signal for outputting an RF signal in one of two frequency bands; and an RF transceiver (11) comprising a dual band receiver that receives RF signals in the first frequency band and in the second, higher frequency band, and a dual band transmitter that transmits RF signals in the same frequency bands. The dual band receiver includes a first receiver chain that operates in the first frequency band as a single conversion receiver having a downconversion mixer that is preceded by a first filter and that is followed by second filter, and a second receiver chain that operates in the second frequency band as a dual conversion superheterodyne receiver having a first downconversion mixer preceded by a first filter and followed by a second filter coupled to a second downconversion mixer followed by a third filter. The downconversion mixer of the single conversion receiver is also the second downconversion mixer of the dual conversion superheterodyne receiver, and the second filter of the single conversion receiver is also the third filter of the dual conversion superheterodyne receiver. The dual band transmitter includes a modulator that outputs a modulated RF signal. When operating in the first frequency band the input RF signal to the modulator has a frequency that is equal to the transmitted RF signal, and when operating in the second frequency band the input RF signal has a frequency that is equal to one half of the transmitted RF signal.

Claims

1. A multiband user terminal, comprising:

a controller for outputting a BAND signal for specifying operation in at least one of a first frequency band or a second, higher frequency band;

a single frequency synthesizer that is responsive to said BAND signal for outputting a local oscillator RF signal when operating in said first frequency band or said second frequency band; and

an RF transceiver comprising a multiband receiver that receives RF signals in said first frequency band and in said second, higher frequency band, and a multiband transmitter that outputs a transmitted RF signal when operating in said first frequency band or in said second, higher frequency band, wherein said multiband transmitter comprises

a modulator that modulates said local oscillator RF signal in accordance with information to be transmitted and that outputs a modulated RF signal, wherein when operating in said first frequency band said local oscillator RF signal has a frequency that is equal to said transmitted RF signal, and wherein when operating in said second frequency band said local oscillator RF signal has a frequency that is equal to one half of said transmitted RF signal, and further comprising an upconversion mixer having a first input for receiving said modulated RF signal and a second input that receives said local oscillator RF signal, wherein said upconversion mixer upconverts said modulated RF signal, using said local oscillator RF signal, to have a frequency equal to said transmitted RF signal when operating in said second, higher frequency band,

wherein said multiband receiver comprises a first receiver chain that operates in said first frequency band as a single conversion receiver having a downconversion mixer that is preceded by a first filter and that is followed by second filter, and further comprising a second receiver chain that operates in said second frequency band as a dual conversion superheterodyne receiver having a first downconversion mixer preceded by a first filter and followed by a second filter coupled to a second downconversion mixer followed by a third filter, wherein said downconversion mixer of said single conversion receiver is also said second downconversion mixer of said dual conversion superheterodyne receiver, and wherein said second filter of said single conversion receiver is also said third filter of said dual conversion superheterodyne receiver.

2. A multiband user terminal as in claim 1, wherein said first filter of said single conversion receiver is also said second filter of said dual conversion superheterodyne receiver.

3. A multiband user terminal as in claim 1, wherein said first and second downconversion mixers of said dual conversion superheterodyne receiver are both supplied with the same mixing frequency from said single frequency synthesizer.

4. A multiband user terminal as in claim 1, wherein said second filter of said single conversion receiver has a center frequency in a range of approximately 45 MHz to approximately 60 MHz.