Time division multiplexing connection transceiver and its receiving automatic gain control method

• US 20040264392A1
• Filed: 07/29/2003
• Published: 12/30/2004
• Est. Priority Date: 01/29/2001
• Status: Abandoned Application

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Mochizuki, Takuji
• Application Number:
  US10/470,468
• Publication Number:
  US 20040264392A1
• Time in Patent Office: Days
• US Class Current: 370/282
• 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
• CPC Class Codes: H04B 1/54 using the same frequency for two directions of communication H04B1/44 takes precedence
• CPC Class Codes: H04B 1/56 with provision for simultaneous communication in two directions

Abstract

An RF switch 12 is connected to a receiving unit 2 at a reception timing. An RF signal received by an antenna 11 is inputted to an amplifying unit 5 via an isolator 3 and an RF filter 4. The RF signal is subjected to automatic gain amplification and is inputted to a demodulating unit 6. An RSSI 61 detects the level of a reception signal. When the detection value is over a threshold, a demodulator 62 controls the RF switch so as to change the switch to a transmitting unit 7 which does not output and send the signal. Consequently, the input of the receiving unit is largely attenuated. The isolator maintains the matching of the input impedance of the amplifying unit and ensures the low-noise property and stability, irrespective of a switching state of the change-over switch.

Claims

1. (Amended) a time-division multiplexing and connecting transceiver for transmitting and receiving a radio frequency signal based on time division at different timings by sharing an antenna, said time-division multiplexing and connecting transceiver comprising:

a change-over switch being directly connected with said antenna for switching and connecting said antenna to one of a transmitting system and a receiving system; and

control means for switching said change-over and outputting a transmission signal to said antenna at a transmission timing, for determining a reception level of a reception signal at a reception timing, for switching said change-over switch to the receiving system and the reception signal from said antenna to the receiving system when the reception level is not more than a predetermined value, and for switching said change-over switch to the transmitting system and inputting the signal largely attenuated and leaked front said antenna to the receiving system when the reception level is more than said predetermined value,

said receiving system includes an isolator which converts an impedance into that matches the best noise and which matches an input impedance of a first amplifier irrespective of a switching state of the change-over switch, an automatic gain control amplifier which serves as an amplifier for amplifying a radio frequency signal and an intermediate frequency signal, and a demodulating means for demodulating data from the reception signal.

2. (Amended) A time division multiplexing and connecting transceiver according to claim 1, wherein said isolator is arranged between said change-over switch and said automatic gain control amplifier.

3. (Amended) A time-division multiplexing and connecting transceiver according to claim 2, wherein said demodulating means comprises a determining means for determining a reception level of the reception signal and a switching means for switching said change-over switch to the transmission system in case where the reception level exceeds the predetermined value.

4. (Amended) A time-division multiplexing and connecting transceiver according to claim 3, wherein an input potion of said automatic gain control amplifier is connected with said change-over switch through said isolator, an arbitrary number of an output portion of said automatic gain control amplifier are provided so as to be connected with said demodulating means, and the automatic gain control of the reception signal is performed individually by said change-over switch and said automatic gain control amplifier.

5. (Amended) An automatic gain control method for reception of a time-division multiplexing and connecting transceiver for transmitting and receiving a radio frequency signal based on time division at different timings by sharing an antenna, said automatic gain control method for reception comprising:

a step of determining a reception level of a reception signal at a reception timing;

a step of switching a change-over switch for switching and connecting said antenna to one of a transmitting system and a receiving system when the reception level is not more than a predetermined value and directly inputting the reception signal from said antenna to the receiving system;

a step of switching said change-over switch to the transmitting system;

converting the signal largely attenuated and leaked from said antenna into that matches the best noise irrespective of the a switching state of said change-over switch;

matching an input impedance of said first amplifier;

performing the automatic gain control individually by said change-over switch and said automatic gain control amplifier which is provided, as an amplifier of a radio frequency signal and an intermediate frequency signal, between said change-over switch and said demodulating means for demodulating data from the reception signal; and

demodulating data from the reception signal.

6. (Deleted)