DUPLEXER WITH SIGNAL CANCELLATION

• US 20170207902A1
• Filed: 11/21/2014
• Published: 07/20/2017
• Est. Priority Date: 11/26/2013
• Status: Active Grant

• Current Assignee: Abdul-Karim Lakhani, Harry Davis
• Original Assignee: Abdul-Karim Lakhani
• Inventors: LAKHANI, Abdul-Karim, DAVIS, Harry
• Granted Patent: US 10,454,662 B2
• Time in Patent Office: Days
• CPC Class Codes: H04B 1/525 with means for reducing leakage of transmitter signal into the receiver
• CPC Class Codes: H04B 7/2628 using code-division multiple access [CDMA] or spread spectrum multiple access [SSMA] H04B7/2618 takes precedence
• CPC Class Codes: H04L 5/1461 Suppression of signals in the return path, i.e. bidirectional control circuits

Abstract

There is provided a duplexer having first, second and third ports and adapted for connection between an antenna and uplink and downlink, respectively, in a full duplex communication system. The duplexer has first and second quarter wave transformers connected between the first and third and between the first and second ports, respectively. The duplexer has a balancing resistor connected between the third port and the output of the second transformer. The duplexer has a filter circuit connected between the output of the second transformer and the second port.

Claims

1. A duplexer having first, second and third ports and adapted for connection between an antenna and uplink and downlink, respectively, in a full duplex communication system, said duplexer comprising:

first and second quarter wave transformers connected between said first and third ports and between said first and second ports, respectively;

a balancing resistor connected between said third port and the output of said second transformer; and

a filter circuit connected between said output of said second transformer and said second port.

2. The duplexer as in claim 1 wherein said filter circuit comprises a bandpass filter.

3. The duplexer as in claim 1 wherein said filter circuit comprises a heterodyne receiver.

4-11. -11. (canceled)

12. A method of making a duplexer with cancellation and separation, said method comprising:

modifying a Wilkinson combiner having a first port with first and second quarter wave transformers connected between a second port and said first port and between a third port and said first port respectively and a balancing resistor connected between said second and third ports, the Wilkinson combiner being modified by connecting a bandpass filter circuit to said second quarter wave transformer and said balancing resistor at one end and the third port at the other end.

13-19. -19. (canceled)

20. A full duplex wireless communication system in which transmit and receive signals are transmitted between a base station and a plurality of subscriber equipment at first and second frequencies which are vanishingly close, each of said base station and subscriber equipment comprising a cancellation/separation duplexer having a transmit port and a receive port and being operative to shift the phase of any transmit signal at one of said transmit ports 180 degrees at the corresponding receive port.

21. The system as in claim 20 comprising cancellation/separation duplexers with first and second quarter wave transformers operative to shift the phase of any transmit signal 180 degrees.

22. The system as in claim 20 in which said subscriber equipment comprises customer premises equipment.

23. The system as in claim 20 in which said subscriber equipment comprises mobile devices.

24-33. -33. (canceled)

34. In a full duplex wireless communication system, the duplex wireless communication system transmitting and receiving signals at the same frequency encoded in first and second encoding techniques, respectively.

35. In the full duplex wireless communication system as in claim 34, wherein the full duplex wireless communication system comprises cancellation/separation duplexers.

36. In the full duplex wireless communication system as in claim 34 wherein said first and second encoding techniques comprised frequency and amplitude modulation.

37. In the full duplex wireless communication system as in claim 34, wherein the transmit and receive signals are encoded in CDMA.

38-42. -42. (canceled)