Systems and Methods for Minimizing Insertion Loss in a Multi-Mode Communications System

• US 20130064064A1
• Filed: 09/09/2011
• Published: 03/14/2013
• Est. Priority Date: 09/09/2011
• Status: Active Grant

• Current Assignee: pSemi Corporation (Murata Manufacturing Co Limited)
• Original Assignee: Peregrine Semiconductor Corporation (Murata Manufacturing Co Limited)
• Inventors: Nobbe, Dan William
• Granted Patent: US 9,065,540 B2
• Time in Patent Office: Days
• US Class Current: 370/201
• CPC Class Codes: H03H 2007/013 Notch or bandstop filters
• CPC Class Codes: H03H 2210/036 Stepwise
• CPC Class Codes: H03H 7/0115 comprising only inductors and capacitors H03H7/075, H03H7/09, H03H7/12, H03H7/13 take precedence
• CPC Class Codes: H03H 7/0161 Bandpass filters H03H7/12 takes precedence
• CPC Class Codes: H03H 7/465 having variable circuit topology, e.g. including switches
• CPC Class Codes: H04B 1/406 with more than one transmission mode, e.g. analog and digital modes
• CPC Class Codes: H04L 5/14 Two-way operation using the same type of signal, i.e. duplex

Abstract

Methods and system for using a multifunctional filter to minimize insertion loss in a multimode communications system are described. Specifically described is a multifunctional filter that is configurable to operate in a bandpass mode when a first type of signal is propagated through the multifunctional filter, and to operate in a lowpass mode when a second type of signal is propagated through the multifunctional filter. The multifunctional filter presents a lower insertion loss to the second type of signal when operating in the lowpass mode than in the bandpass mode.

Claims

1. A method of minimizing insertion loss in at least one of two types of signals propagated through a communications system, the method comprising:

configuring a multifunctional filter to operate in a bandpass mode when a first type of signal is propagated through the multifunctional filter; and

configuring the multifunctional filter to operate in a lowpass mode when a second type of signal is propagated through the multifunctional filter, the lowpass mode providing a lower insertion loss upon the second type of signal than the bandpass mode.

2. The method of claim 1, wherein the first type of signal is a frequency division duplex signal and the second type of signal is a time division duplex signal.

3. The method of claim 2, wherein the multifunctional filter is a part of a duplexer unit that accommodates duplex signal transmission in the communications system.

4. The method of claim 3, further comprising:

configuring the multifunctional filter to provide a notchtype attenuation upon at least one harmonic component of the time division duplex signal.

5. The method of claim 3, wherein configuring the multifunctional filter to operate in the lowpass mode comprises removing at least one filter component from a signal propagation path of the second type of signal.

6. The method of claim 5, wherein the signal propagation path is a receive signal path in the duplexer unit.

7. The method of claim 6, wherein removing the at least one filter component from the signal propagation path comprises eliminating all elements of the multifunctional filter in the receive signal path.

8. A method of minimizing insertion loss in a duplexer, the method comprising:

configuring the duplexer to operate in a bandpass mode when a first type of signal is propagated through the duplexer; and

configuring the duplexer to operate in a lowpass mode when a second type of signal is propagated through the duplexer, the lowpass mode providing a lower insertion loss upon the second type of signal than the bandpass mode.

9. The method of claim 8, wherein the first type of signal is a frequency division duplex signal, the second type of signal is a time division duplex signal, and wherein configuring the duplexer to operate in one of the bandpass or lowpass modes comprises configuring a multifunctional filter contained in the duplexer.

10. The method of claim 9, further comprising:

configuring the multifunctional filter to provide a notchtype attenuation upon at least one harmonic component of the time division duplex signal.

11. The method of claim 8, wherein the first type of signal is a frequency division duplex signal, the second type of signal is a time division duplex signal, and configuring the duplexer to operate in the lowpass mode comprises removing at least one filter component from a signal propagation path of the second type of signal.

12. The method of claim 11, further comprising coupling the duplexer to a receiver unit, and wherein the signal propagation path is a receive signal path configured to direct a signal received at the duplexer into the receiver.

13. The method of claim 12, wherein removing the at least one filter component from the receive signal path comprises eliminating all elements of the multifunctional filter in the receive signal path.

14. A communications system comprising:

a multifunctional filter that is configurable to operate in a bandpass mode when a first type of signal is propagated through the multifunctional filter, and to operate in a lowpass mode when a second type of signal is propagated through the multifunctional filter, the multifunctional filter presenting a lower insertion loss to the second type of signal when operating in the lowpass mode than in the bandpass mode.

15. The system of claim 14, wherein the first type of signal is a frequency division duplex signal and the second type of signal is a time division duplex signal.

16. The system of claim 15, wherein the multifunctional filter is a part of a duplexer unit contained inside a multimode cellular phone that is selectively operable in a frequency division duplex mode or a time division duplex mode.

17. The system of claim 14, wherein the multifunctional filter comprises multiple filter stages and at least one of the multiple filter stages is selectively eliminated when the second type of signal is propagated through the multifunctional filter.

18. The system of claim 17, further comprising a receiver, and wherein the at least one of the multiple filter stages is selectively eliminated in a receive signal path through which a signal is routed to the receiver.

19. The system of claim 14, further comprising a signal detection circuit configured to detect the presence of one of the first or the second type of signal and automatically configure the multifunctional filter to operate in the bandpass mode or the lowpass mode respectively.

20. The system of claim 14, further comprising at least one of a switch or a variable impedance device for configuring the multifunctional filter to operate in one of the bandpass mode or the lowpass mode.