Radio tranceiver for data communications

• US 6,278,864 B1
• Filed: 09/21/1999
• Issued: 08/21/2001
• Est. Priority Date: 04/20/1995
• Status: Expired due to Fees

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Cummins, James D., Thomson, Bradley E., Kern, William F., Dinh, Duong X.
• Primary Examiner(s): Hunter, Daniel
• Assistant Examiner(s): Armstrong, Darnell R
• Application Number:
  US09/400,706
• Time in Patent Office: 700 Days
• Field of Search: 455/78, 455/82, 455/83, 455/86, 455/74, 455/89, 455/90, 455/128, 455/95, 455/260, 455/265, 455/69, 235/492, 375/78, 379/93, 379/94, 379/99, 379/96, 379/97, 379/98
• US Class Current: 455/73
• CPC Class Codes: H04B 1/1615 Switching on; Switching off, e.g. remotely battery saving circuits associated with selective call operation H04W52/00; details of power consumption reduction in a PLL, H03L7/0802, H03L7/14, H03L2207/08, H03L2207/18; muting amplifiers by gain control see H03G3/34
• CPC Class Codes: H04B 1/38 Transceivers, i.e. devices in which transmitter and receiver form a structural unit and in which at least one part is used for functions of transmitting and receiving
• CPC Class Codes: H04W 52/0274 by switching on or off the equipment or parts thereof
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A compact low-power radio frequency (RF) transceiver with a built-in antenna provides wireless communication between a computer and another device. A direct conversion receiver together with a voltage controlled oscillator, phase lock loop circuits, digitally controlled divider circuits and a patch antenna are packaged into a compact enclosure, having dimensions within the PCMCIA format. In some embodiments, the transceiver enters a sleep mode whenever it is idle in order to further conserve power. In other embodiments, a signature detector enables the transceiver to distinguish between noise and valid messages by recognizing a signature word embedded in the data packet.

Claims

1. A radio frequency (RF) transceiver comprising:

an RF transmitter section;

an RF receiver section;

an antenna terminal;

a transmit/receive (T/R) switching section comprising a first and a second switch, said T/R switching section having an RF transmit input terminal for receiving an RF transmit signal, a receiver input terminal coupled to said antenna terminal, a receiver output terminal coupled to said RF receiver section, an RF output terminal coupled to said antenna terminal, and control signal input terminals, said first switch of said T/R switching section being operable to selectively connect said receiver input terminal to said receiver output terminal, and said second switch of said T/R switching section being operable to selectively connect said RF transmit input terminal to said RF output terminal;

a transmit/local oscillator (T/LO) switching section comprising a first and a second switch, said T/LO switching section having an RF transmit input terminal for receiving RF transmit signals from the RF transmitter section, a local oscillator input terminal for receiving a local oscillator signal, an RF transmit output terminal, a local oscillator output terminal for providing a local oscillator signal to said RF receiver section, and control signal input terminals, said first switch of said T/LO switching section being operable to selectively connect said RF transmit input terminal to said RF transmit output terminal, and said second switch of said T/LO switching section being operable to selectively connect said local oscillator input terminal to said local oscillator output terminal;

means coupling said RF transmit output terminal of said T/LO switching section to said RF transmit input terminal of said T/R switching section; and

a control circuit coupled to said control input terminals of said T/R switching section and said T/LO switching section, said control circuit including means for providing transmit mode control signals to said T/R switching section and said T/LO switching section, wherein in response to receipt of transmit mode control signals said first switch of said T/LO switching section is closed and said second switch of said T/LO switching section is opened, and further wherein said first switch of said T/R switching section is opened and said second switch of said T/R switching section is closed.

2. A radio frequency (RF) transceiver according to claim 1, wherein said control circuit further includes means for providing receive mode control signals to said control input terminals of said T/R switching section and said T/LO switching section, wherein in response to receipt of receive mode control signals, said first switch of said T/R switching section is closed and said second switch of said T/R switching section is opened, and further wherein said first switch of said T/LO switching section is opened and said second switch of said T/LO switching section is closed.

3. A radio frequency (RF) transceiver according to claim 1, wherein said first and second switches of said T/R switching section, and said first and second switches of said T/LO switching section each comprise field effect transistor devices.