Radio-Receiver Front-End and A Method For Frequency Converting An Input Signal

• US 20070287403A1
• Filed: 07/06/2005
• Published: 12/13/2007
• Est. Priority Date: 07/06/2004
• Status: Abandoned Application

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Sjoland, Henrik
• Application Number:
  US11/571,614
• Publication Number:
  US 20070287403A1
• Time in Patent Office: Days
• US Class Current: 455/326
• CPC Class Codes: H03D 2200/0043 Bias and operating point
• CPC Class Codes: H03D 2200/0047 Offset of DC voltage or frequency
• CPC Class Codes: H03D 2200/0088 Reduction of intermodulation, nonlinearities, adjacent channel interference; intercept points of harmonics or intermodulation products
• CPC Class Codes: H03D 7/1433 using bipolar transistors H03D7/145 takes precedence
• CPC Class Codes: H03D 7/1441 using field-effect transistors H03D7/145 takes precedence
• CPC Class Codes: H03D 7/145 using a combination of bipolar transistors and field-effect transistors
• CPC Class Codes: H03D 7/1458 Double balanced arrangements, i.e. where both input signals are differential
• CPC Class Codes: H03D 7/1483 comprising components for selecting a particular frequency component of the output
• CPC Class Codes: H03D 7/165 at least two frequency changers being located in different paths, e.g. in two paths with carriers in quadrature combined with amplitude demodulation H03D1/2245, combined with angle demodulation H03D3/007; N-path filters H03H19/002
• CPC Class Codes: H04B 1/109 by improving strong signal performance of the receiver when strong unwanted signals are present at the receiver input

Abstract

An N-phase radio receiver front-end for converting an input signal having a first frequency to output signals having a second frequency, and a method for converting an input signal in an N-phase radio receiver front-end. An input port of the N-phase radio receiver front-end is directly connected to an input port of a low noise amplifier (50). A mixer arrangement (50a) is a current mode mixer arrangement. An output port of the low-noise amplifier is directly connected to an input port of the mixer arrangement. A signal generator operatively connected to the mixer arrangement is adapted to generate N phase shifted local oscillator signals.

Claims

1. An N-phase radio receiver front-end for converting an input signal having a first frequency to an output signal having a second frequency, comprising an input port, a low noise amplifier (50, 60) having an input port and an output port, a mixer arrangement (50a) having an input port and an output port, and a signal generator adapted to generate N local oscillator signals and being operatively connected to the mixer arrangement characterized in that the input port of the N-phase radio receiver front-end is directly connected to the input port of the low noise amplifier (50, 60);

the mixer arrangement (50a) is a current mode mixer arrangement;

the output port of the low noise amplifier is directly connected to the input port of the mixer arrangement; and

the signal generator is adapted to generate N phase shifted local oscillator signals.

2. The N-phase radio receiver front end according to claim 1, wherein the mixer arrangement (50a) includes N/2 mixer cores (51, 52), each mixer core having an input terminal connected directly to the input port of the mixer arrangement.

3. The N-phase radio receiver front-end according to claim 2, wherein said mixer cores (51, 52) are single-balanced mixer cores or double balanced mixer cores.

4. The N-phase radio receiver front end according to any of the previous claims, wherein said low noise amplifier is a differential amplifier (160a, 160b) or a single-ended amplifier (60).

5. The N-phase radio receiver front-end according to claim 2 or 3, wherein each mixer core (51, 52) comprises two or four transistors (61a, 62a, 61b, 62b, 161a, 161b, 161c, 161c, 162a, 162b, 162c, 162d), the transistors of each mixer core being responsive to two different local oscillator signals.

6. The N-phase radio receiver front-end according to any of the previous claims, wherein the signal generator is an oscillator for providing the local oscillator signals for driving the mixer arrangement (50a).

7. The N-phase radio receiver front-end according to any of the previous claims, wherein the signal generator is an oscillator operatively connected to the mixer arrangement (50a) by means of transformers (75, 77, 81, 82) for providing the local oscillator signals at local oscillator input terminals of said mixer arrangement (50a).

8. The N-phase radio receiver front end according to claim 7, wherein the oscillator is a quadrature oscillator for providing quadrature local oscillator signals.

9. The N-phase radio receiver front-end according to claim 7 or 8, wherein the oscillator comprises LC-tanks, each LC-tank being provided by an inductor (75, 77) and a capacitor (76, 78).

10. The N-phase radio receiver front-end according to claim 9, wherein the inductors (75, 77) of the LC-tanks provide primary windings of the transformers, and wherein inductors (81, 82) connected to the local oscillator input terminals of the mixer arrangement (50a) provide secondary windings of said transformers.

11. The N-phase radio receiver front-end according to claim 9 or 10, wherein the capacitor (76, 78) of each LC-tank is a variable capacitor for adjusting the frequency of the local oscillator signals.

12. The N-phase radio receiver front-end according to any of the claims 1 to 6, wherein the signal generator comprises a high frequency oscillator (90) and a frequency divider (91) for providing the local oscillator signals.

13. The N-phase radio receiver front-end according to claim 12, wherein the frequency divider (91) is arranged to provide N local oscillator signals having a duty cycle of substantially 1/N each, and only one of said local oscillator signals being in the high state at a time.

14. The N-phase radio receiver front-end according to any of the previous claims, wherein the low noise amplifier (50) comprises at least one input transistor (60) connected in a common gate or a common base configuration.

15. The N-phase radio receiver front-end according to any of the previous claims, further comprising an active or passive frequency selective load connected to output ports of the mixer arrangement (50a).

16. The N-phase radio receiver front-end according to claim 15, wherein the frequency selective load comprises current to voltage conversion means (53, 54, 63a, 64a, 65a, 66a, 63b, 64b, 65b, 66b, 67a, 67b).

17. The N-phase radio receiver front-end according to claim 16, wherein an output port of a first mixer core (51) of the mixer arrangement (50a) is connected to a first current to voltage conversion means and an output port of a second mixer core (52) of the mixer arrangement is connected to a second current to voltage conversion means.

18. The N-phase radio receiver front-end according to claim 17, wherein each current to voltage conversion means (53, 54, 63a, 64a, 65a, 66a, 63b, 64b, 65b, 66b, 67a, 67b) comprises a mixer load connected to a respective output port of the mixer cores and signal grounding means, respectively.

19. The N-phase radio receiver front-end according to claim 18, wherein each mixer load is a resistor (63a, 65a, 63b, 65b) connected in parallel with a capacitor (64a, 66a, 64b, 66b), and a capacitor (67a, 67b) connected between the output terminals of each mixer core.

20. The N-phase radio receiver according to claim 19, wherein the capacitors (64a, 66a, 64b, 66b, 67a, 67b) of each mixer load has a value which is effective for suppressing out-of-band interference of a signal input to the radio receiver front-end when said signal has been mixed.

21. The N-phase radio receiver front-end according to claim 20, wherein the capacitance of each capacitor (64a, 66a, 64b, 66b, 67a, 67b) of each mixer load is variable for suppressing out-of-band interference of input signals of different received signal bandwidths.

22. The N-phase radio receiver front-end according to any of the previous claims, further comprising a current device (68) connected to the input port of the low noise amplifier and grounding means.

23. The N-phase radio receiver front-end according to claim 22, wherein the current device (68) is an inductor, a resistor, or a transistor connected as a current source.

24. The N-phase radio receiver front end according to any of the previous claims, wherein said N-phase radio receiver front end is a quadrature radio receiver front-end.

25. Use of an N-phase radio receiver front-end according to any of the previous claims in a wireless electronic communication apparatus (1) for converting an input signal having a first frequency to a signal having a second frequency.

26. A wireless electronic communication apparatus (1) comprising an N-phase radio receiver front-end according to any of claims 1-24.

27. The wireless electronic communication apparatus according to claim 23, wherein the wireless electronic communication apparatus (1) is a mobile radio terminal, a pager, a communicator, an electronic organizer or a smartphone.

28. The wireless electronic communication apparatus according to claim 23, wherein the wireless electronic communication apparatus is a mobile telephone (1).

29. A method for converting an input signal having a first frequency to an output signal having a second frequency in an N-phase radio receiver front-end, the method comprising the step of receiving the input signal at an input port of the radio receiver front-end, characterized by the steps of

amplifying the input signal comprising out-of-band interference in a low noise amplifier (50, 60);

mixing the input signal and the out-of-band interference with a plurality of phase shifted local oscillator signals having a second frequency in a current mode mixer arrangement (50a) to generate a mixed signal having the second frequency.

30. The method according to claim 29, wherein the mixed signal comprises out-of-band interference;

and the method further comprises suppressing the out-of-band interference of the mixed signal using a frequency selective load.

31. The method according to claim 30, wherein the step of suppressing comprises supplying the mixed signal comprising the out-of-band interference to a frequency selective load (53, 54, 63a, 64a, 65a, 66a, 63b, 64b, 65b, 66b, 67a, 67b), which is connected to an output port of the mixer arrangement (50a) and signal grounding means, respectively.

32. The method according to claim 31, wherein the step of suppressing comprises supplying the mixed signal comprising the out-of-band interference to a resistor (63a, 65a, 63b, 65b) connected in parallel with a capacitor (64a, 66a, 64b, 66b), and to a capacitor (67a, 67b) connected between output terminals of the mixer arrangement.

33. The method according to claim 32, wherein the step of suppressing comprises suppressing by means of the capacitors (64a, 66a, 64b, 66b, 67a, 67b), which have values that are effective for suppressing out-of-band interference of the mixed signal.

34. The method according to claim 33, further comprising adjusting the capacitance of capacitors (64a, 66a, 64b, 66b, 67a, 67b), which are variable capacitors, of the frequency selective load for suppressing out-of-band interference of mixed input signals of different received signal bandwidths.

35. The method according to any of the claims 29 to 34, further comprising the step of generating the local oscillator signals, and supplying said generated local oscillator signals to a first and a second single balanced or double balanced mixer cores (51, 52) of the mixer arrangement (50a).

36. The method according to claim 35, further comprising adjusting the capacitance of a capacitor (76, 78) of an oscillator connected to the mixer arrangement (50a) for adjusting the frequency of said local oscillator signals.