Dual mode phone architecture utilizing a single transmit-receive switch

• US 6,510,310 B1
• Filed: 01/26/1998
• Issued: 01/21/2003
• Est. Priority Date: 01/26/1998
• Status: Expired due to Term

• Current Assignee: Skyworks Solutions Incorporated
• Original Assignee: Conexant Systems Incorporated (Synaptics Incorporated)
• Inventors: Muralidharan, Raghunathan
• Primary Examiner(s): Kincaid; Lester G.
• Application Number:
  US09/013,235
• Time in Patent Office: 1,821 Days
• Field of Search: 455/83,84,552,553,73,74,82,103,74.1,131,80,81,78 370/278,280,330,436 375/216 330/175,176,185
• US Class Current: 455/83
• CPC Class Codes: H04B 1/406 with more than one transmission mode, e.g. analog and digital modes
• CPC Class Codes: H04B 1/48 in circuits for connecting transmitter and receiver to a common transmission path, e.g. by energy of transmitter H04B1/46 takes precedence

Abstract

A dual mode phone system utilizes a single transmit-receive (TR) switch. The dual mode system operates in GSM and DCS communication bands. The use of the single switch reduces the circuit board space required for the telephone hand set. Additionally, the architecture for the telephone reduces receiver losses associated with a diplexer in the receive path.

Claims

1. A dual band phone, comprising:

an antenna;

a transmission path including a first transmit power amplifier and a second transmit power amplifier, the first transmit power amplifier providing transmit signals in a first frequency range and the second transmit power amplifier providing transmit signals in a second frequency range;

a first diplexer which receives transmission signals and provides the transmission path with separated transmission signals in the first frequency range to the first transmit amplifier and separated transmission signals in the second frequency range to the second power amplifier;

a receive path including a first filter for receiving receive signals in a third frequency range and a second filter for receiving receive signals in a fourth frequency range;

a first LNA mixer coupled directly to an output of the first filter;

a second LNA mixer coupled directly to an output of the second filter; and

a single GaAs transmit-receive switch having a single antenna interface, a transmit input, and a receive output, the antenna interface being coupled to the antenna, the transmit input being coupled to the transmit path, and the receive output being coupled directly to the first and second filters of the receive path, said antenna, transmission path, receive path, and single transmit-receive switch being adapted to allow the dual band phone to operate on GSM and DCS communication bands wherein the transmission path and receive path are used one at a time, the transmission path is used to transmit within one of the first and second frequency ranges and the receive path is used to receive on one of the third and fourth frequency ranges, and wherein the first, second, third and fourth frequency ranges are all different.

2. The dual band phone of claim 1, wherein the first and third ranges are in a global system for mobile (GSM) band, and the second and fourth ranges are in a digital communication service (DCS) band.

3. The dual band phone of claim 1, further comprising:

a low pass filter coupled between the antenna interface and the antenna.

4. The dual band phone of claim 1, wherein the transmit path further comprises:

a second diplexer coupled between the transmit input and the first and second power amplifiers.

5. The dual band phone of claim 4, further comprising:

a low pass filter coupled between the second diplexer and the transmit input.

6. The dual band phone of claim 4, wherein the first transmit power amplifier is suppressed in a second mode of operation.

7. The dual band phone of claim 6, wherein the second transmit power amplifier is suppressed in a first mode of operation.

8. The dual band phone of claim 4, wherein the switch is a GaAs semiconductor device.

9. A dual band phone architecture, comprising:

a GSM radio transmission unit having a GSM output;

a DCS radio transmission unit having a DCS output;

a first diplexer which separates a transmission signal into a GSM band and a DCS band and which provides a transmit signal to the GSM radio transmission unit and a transmit signal to the DCS radio transmission unit;

at least one receive unit;

a second diplexer having a first input coupled to the GSM output, a second input coupled to the DCS output, and a diplexer output;

a single GaAs transmit-receive switch having a single antenna interface, a transmit input, and a receive output, the transmit input being coupled directly to the diplexer output, and the receive output being coupled directly to the receive unit, said single transmit-receive switch being adapted to allow one of the GSM radio transmission unit and DCS radio transmission to transmit and the at least one receive unit to receive, but not at the same time;

the receive unit further comprising a receive filter coupled directly to the receive output; and

a LNA mixer coupled directly to an output of the filter.

10. The dual band phone architecture of claim 9, wherein the GSM output provides signals between 890 and 915 MHz.

11. The dual band phone architecture of claim 10, wherein the DCS output provides signals between 1710 and 1785 MHz.

12. The dual band phone architecture of claim 11, wherein the receive unit further comprises:

a third diplexer.

13. The dual band phone architecture of claim 12, wherein the switch includes a GaAs substrate.

14. The dual band phone architecture of claim 9, further comprising:

a low pass filter coupled to the antenna interface.

15. The dual band phone architecture of claim 9, further comprising:

a low pass filter coupled between the second diplexer and the transmit input.

16. The dual band phone architecture of claim 9, wherein the GSM transmission unit is suppressed in a DCS mode of operation, and wherein the DCS transmission unit is suppressed in a GSM mode of operation.

17. A dual band phone system, comprising:

an antenna;

a diplexer which receives and separates a transmission signal into a first frequency range and a second frequency range;

a transmission path means coupled to an output of the diplexer for providing transmit signals in the first frequency range and for providing transmit signals in the second frequency range;

a receive path means for receiving receive signals in a third frequency range and for receiving receive signals in a fourth frequency range; and

a single GaAs transmit-receive switch means for connecting the transmission path means to a single antenna or for connecting the receive path means to the single antenna, said antenna, transmission path means, receive path means, and single transmit-receive switch means being adapted to allow the dual band phone to operate on GSM and DCS communication bands wherein the transmission path means and receive path means operate one at a time, the transmission path means is used to transmit on one of the first and second frequency ranges, the receive path means is used to receive on one of the third and fourth frequency ranges, and the first, second, third and fourth frequency ranges are all different, the receive path means further comprising;

a filter directly coupled to the receive path means; and

a LNA mixer directly coupled to an output of the filter.

18. The dual band phone system of claim 17, further comprising:

a low pass filter coupled between the switch means and the antenna.

19. The dual band phone system of claim 18, wherein the switch means is a GaAs device.

20. The dual band phone system of claim 17, wherein the third range is between 1805-1880 MHz, and the fourth range is between 935-960 MHz.