Method and arrangement for transmitting and receiving RF signals through various radio interfaces of communication systems

1. A direct-conversion transceiver capable of operating with a plurality of radio interfaces, comprising:

a first controllable bandpass filter configured to filter a received signal according to a first bandpass control signal that selects one of a plurality of passbands corresponding to a selected one of the plurality of radio interfaces, wherein the first controllable bandpass filter has a signal path common to the plurality of radio interfaces;

a low-noise amplifier configured to amplify the filtered received signal according to a first gain control signal that controls an amount of gain, wherein the low-noise amplifier has a signal path common to the plurality of radio interfaces;

a first programmable synthesizer configured to generate a first mixing signal according to a first mixing control signal corresponding to the selected one of the plurality of radio interfaces, wherein the first programmable synthesizer has a signal path common to the plurality of radio interfaces;

a first frequency divider coupled to the first programmable synthesizer and configured to divide a frequency of the first mixing signal by two to provide a first divided frequency signal according to a first divider control signal corresponding to the selected one of plurality of radio interfaces;

a first mixer coupled to the low-noise amplifier and configured to mix the amplified and filtered received signal with the first divided mixing signal to produce a first baseband quadrature signal, wherein the first mixer has a signal path common to the plurality of radio interfaces and wherein the first mixer produces the first baseband quadrature signal on a basis of two 90-degree phase-shifted components produced from the first frequency divider;

a first low-pass filter coupled to the first mixer and configured to low-pass filter the first baseband quadrature signal according to a first filter control signal corresponding to the selected one of the plurality of radio interfaces, wherein the first low-pass filter has a signal path common to the plurality of radio interfaces;

a first gain-controlled amplifier coupled to the first low-pass filter and configured to provide gain-controlled amplification of the first low-pass filtered baseband quadrature signal, wherein the first gain-controlled amplifier has a signal path common to the plurality of radio interfaces;

an analog-to-digital converter coupled to the first gain-controlled amplifier and configured to convert to digital form an output of the first gain-controlled amplifier;

a digital signal processor configured to receive digital output from the analog-to-digital converter and to further process said digital output;

a digital-to-analog converter coupled to the digital signal processor and configured to receive a second baseband quadrature signal therefrom and to provide analog output signals;

a second low-pass filter coupled to the digital-to-analog converter and configured to low-pass filter the analog output signals from the digital-to-analog converter according to a second filter control signal corresponding to the selected one of the plurality of radio interfaces, wherein the second low-pass filter has a signal path common to the plurality of radio interfaces;

a second programmable synthesizer configured to generate a second mixing signal according to a second mixing control signal corresponding to the selected one of the plurality of radio interfaces, wherein the second programmable synthesizer has a signal path common to the plurality of radio interfaces;

a second frequency divider coupled to the second programmable synthesizer and configured to divide a frequency of the second mixing signal by two to provide a second divided frequency signal according to a second divider control signal corresponding to the selected one of the plurality of radio interfaces;

a second mixer coupled to the second low-pass filter and configured to mix signals from the second low-pass filter and the second frequency divider to produce a carrier-frequency transmission signal, wherein the second mixer has a signal path common to the plurality of radio interfaces and wherein the second mixer produces the carrier-frequency transmission signal on the basis of two 90-degree phase-shifted components produced from the second frequency divider;

a second gain-controlled amplifier coupled to the second mixer and configured to control gain according to a second gain control signal corresponding to the selected one of the plurality of radio interfaces, wherein the second gain-controlled amplifier has a signal path common to the plurality of radio interfaces;

a power amplifier coupled to the second gain-controlled amplifier and configured to produce an amplified output using a frequency band determined on the basis of a power control signal corresponding to the selected one of the plurality of radio interfaces, wherein the power amplifier has a signal path common to the plurality of radio interfaces;

a second controllable bandpass filter configured to filter an output of the power amplifier according to a second bandpass control signal that selects one of a second plurality of passbands corresponding to the selected one of the plurality of radio interfaces, wherein the second controllable bandpass filter has a signal path common to the plurality of radio interfaces; and

a microprocessor configured to generate one or more control signals to cause selection of the selected one of the plurality of radio interfaces, wherein at least one of the plurality of radio interfaces comprises a modulation, a channel spacing, and a channel bit rate that at least one other of the plurality of radio interfaces does not have.

2. A direct-conversion transmitter comprising:

a transmit synthesizer common to a plurality of radio interfaces of the direct-conversion transmitter and configured to generate a mixing signal;

a controllable low-pass filter common to the plurality of radio interfaces of the direct-conversion transmitter, the controllable low-pass filter configured to perform filtering of an analog baseband transmission signal using a controllable cut-off frequency according to which one of the plurality of radio interfaces of the direct-conversion transmitter is selected;

a frequency divider common to the plurality of radio interfaces of the direct-conversion transmitter, the frequency divider configured to divide a frequency of the mixing signal according to which one of the plurality of radio interfaces of the direct-conversion transmitter is selected, wherein the dividing produces two mixing signal components having a 90-degree phase difference; and

a controllable gain transmitter amplifier common to the plurality of radio interfaces of the direct-conversion transmitter and configured to amplify a carrier-frequency signal from a mixer at a gain controlled according to which one of the plurality of radio interfaces of the direct-conversion transmitter is selected, wherein at least one of the plurality of radio interfaces of the direct-conversion transmitter comprises a modulation, a channel spacing, and a channel bit rate that at least one other of the plurality of radio interfaces of the direct-conversion transmitter does not have.

3. The direct-conversion transmitter of claim 2 , wherein the frequency divider is configured to divide the frequency of the mixing signal so as to correspond to a selected transmission frequency band of a radio interface of the plurality of radio interfaces.

4. The direct-conversion transmitter of claim 3 , wherein a first radio interface of the plurality of radio interfaces employs a WCDMA system and a second radio interface of the plurality of radio interfaces employs a Global System for Mobile communications (GSM) system.

5. The direct-conversion transmitter of claim 3 , wherein the direct-conversion transmitter is part of a transceiver that comprises a direct-conversion receiver.

6. The direct-conversion transmitter of claim 3 , wherein the controllable low-pass filter and the controllable gain transmitter amplifier are part of a transmit path common to the plurality of radio interfaces.

7. The direct-conversion transmitter of claim 3 , wherein a first radio interface of the plurality of radio interfaces employs a WCDMA system and a second radio interface of the plurality of radio interfaces employs a Global System for Mobile communications (GSM) system, and wherein the controllable low-pass filter and the controllable gain transmitter amplifier are part of a transmit path common to the plurality of radio interfaces.

8. The direct-conversion transmitter of claim 3 , further comprising a power amplifier configured to amplify the carrier-frequency signal amplified by the controllable gain transmitter amplifier, the power amplifier having a controllable operating frequency band set according to which one of the plurality of radio interfaces is selected.

9. The direct-conversion transmitter of claim 2 , wherein the frequency divider comprises a control input that determines a divisor by which the frequency of the mixing signal is divided.

10. The direct-conversion transmitter of claim 2 , wherein the frequency divider is configured to produce the two mixing signal components as quotients of the division of the frequency of the mixing signal.

11. The direct-conversion transmitter of claim 10 , wherein the frequency divider is configured to produce the two mixing signal components without the use of a phase shifter after the division of the frequency of the mixing signal.

12. The direct-conversion transmitter of claim 2 , wherein the frequency divider is configured to produce the two mixing signal components using a phase shifter after the division of the frequency of the mixing signal.

13. The direct-conversion transmitter of claim 2 , wherein the frequency divider comprises a controllable frequency divider.

14. The direct-conversion transmitter of claim 2 , wherein the frequency divider is configured to divide the frequency of the mixing signal at least by two.

15. The direct-conversion transmitter of claim 14 , wherein the frequency divider comprises a controllable frequency divider.

16. The direct-conversion transmitter of claim 2 , wherein the frequency divider is configured to divide the frequency of the mixing signal at least by two and by four.

17. The direct-conversion transmitter of claim 16 , wherein the frequency divider is a controllable frequency divider.

18. The direct-conversion transmitter of claim 2 , wherein the frequency divider is configured to divide the frequency of the mixing signal by different divisors determined according to which one of the plurality of radio interfaces of the direct-conversion transmitter is selected.

19. The direct-conversion transmitter of claim 18 , wherein a first radio interface of the plurality of radio interfaces employs a WCDMA system and a second radio interface of the plurality of radio interfaces employs a Global System for Mobile communications (GSM) system.

20. The direct-conversion transmitter of claim 18 , wherein the direct-conversion transmitter is part of a transceiver that comprises a direct-conversion receiver.

21. The direct-conversion transmitter of claim 18 , wherein the controllable low-pass filter and the controllable gain transmitter amplifier are part of a transmit path common to the plurality of radio interfaces.

22. The direct-conversion transmitter of claim 18 , wherein a first radio interface of the plurality of radio interfaces employs a WCDMA system and a second radio interface of the plurality of radio interfaces employs a Global System for Mobile communications (GSM) system, and wherein the controllable low-pass filter and the controllable gain transmitter amplifier are part of a transmit path common to the plurality of radio interfaces.

23. The direct-conversion transmitter of claim 18 , further comprising a power amplifier configured to amplify the carrier-frequency signal amplified by the controllable gain transmitter amplifier, the power amplifier having a controllable operating frequency band set according to which one of the plurality of radio interfaces is selected.

24. The direct-conversion transmitter of claim 18 , wherein the controllable low-pass filter, the mixer, and the controllable gain transmitter amplifier are part of a transmit path common to the plurality of radio interfaces.

25. The direct-conversion transmitter of claim 2 , wherein the controllable gain transmitter amplifier is configured to perform automatic gain control.

26. The direct-conversion transmitter of claim 2 , wherein at least two of the plurality of the radio interfaces of the direct conversion transmitter have different transmission frequencies.

27. The direct-conversion transmitter of claim 2 , wherein at least two of the plurality of the radio interfaces of the direct conversion transmitter have different transmission frequency ranges.

28. The direct-conversion transmitter of claim 2 , wherein at least two of the plurality of the radio interfaces of the direct conversion transmitter have overlapping transmission frequency ranges.

29. The direct-conversion transmitter of claim 2 , wherein at least two of the plurality of the radio interfaces of the direct conversion transmitter have transmission frequency ranges that are the same.

30. The direct-conversion transmitter of claim 2 , wherein at least two of the plurality of the radio interfaces of the direct conversion transmitter have adjacent transmission frequency ranges.

31. The direct-conversion transmitter of claim 2 , wherein a first radio interface of the plurality of radio interfaces of the direct conversion transmitter operates at a first transmission frequency, wherein a second radio interface of the plurality of the radio interfaces of the direct conversion transmitter operates at a second transmission frequency, and wherein the first transmission frequency and the second transmission frequency are within 100 MHz of each other.

32. The direct-conversion transmitter of claim 2 , wherein a separation of respective transmission frequencies of at least two of the plurality of radio interfaces ranges from 0 MHz to 1156 MHz.

33. The direct-conversion transmitter of claim 2 , wherein a first transmission frequency of the at least one of the plurality of radio interfaces of the direct-conversion transmitter and a second transmission frequency of the least one other of the plurality of radio interfaces of the direct-conversion transmitter differ by 91 MHz to 132 MHz.

34. The direct-conversion transmitter of claim 2 , wherein a first radio interface of the plurality of radio interfaces employs a time division multiple access method and a second radio interface of the plurality of radio interfaces employs a code division multiple access method.

35. The direct-conversion transmitter of claim 2 , wherein a first radio interface of the plurality of radio interfaces employs a WCDMA system and a second radio interface of the plurality of radio interfaces employs a Global System for Mobile communications (GSM) system.

36. The direct-conversion transmitter of claim 2 , wherein the direct-conversion transmitter is part of a transceiver that comprises a direct-conversion receiver.

37. The direct-conversion transmitter of claim 2 , wherein the plurality of radio interfaces further differ from each other by multiple access method.

38. The direct-conversion transmitter of claim 2 , wherein the plurality of radio interfaces further differ from each other by duplex method.

39. The direct-conversion transmitter of claim 2 , wherein the plurality of radio interfaces further differ from each other by RF bandwidth.

40. The direct-conversion transmitter of claim 2 , further comprising a control block circuit configured to generate at least one control signal that indicates which of the plurality of radio interfaces is selected, wherein the control block circuit comprises a microprocessor.

41. The direct-conversion transmitter of claim 2 , wherein the carrier-frequency signal comprises a signal from the mixing signal components mixed with the analog baseband transmission signal filtered by the controllable low-pass filter.

42. The direct-conversion transmitter of claim 2 , wherein the controllable gain transmitter amplifier is configured to amplify the carrier-frequency signal through a signal path that is common to each of the plurality of radio interfaces.

43. The direct-conversion transmitter of claim 2 , wherein the controllable low-pass filter is configured to filter the analog baseband transmission signal through a signal path that is common to each of the plurality of radio interfaces.

44. The direct-conversion transmitter of claim 2 , wherein the controllable low-pass filter and the controllable gain transmitter amplifier are part of a transmit path common to the plurality of radio interfaces.

45. The direct-conversion transmitter of claim 2 , further comprising the mixer wherein the mixer is configured to generate the carrier-frequency signal from the two mixing signal components and the analog baseband transmission signal filtered by the controllable low-pass filter.

46. The direct-conversion transmitter of claim 45 , wherein the mixer is configured to generate the carrier-frequency signal through a signal path that is common to each of the plurality of radio interfaces.

47. The direct-conversion transmitter of claim 45 , wherein the controllable low-pass filter and the mixer are part of a transmit path common to the plurality of radio interfaces.

48. The direct-conversion transmitter of claim 45 , wherein the mixer, and the controllable gain transmitter amplifier are part of a transmit path common to the plurality of radio interfaces.

49. The direct-conversion transmitter of claim 45 , wherein the controllable low-pass filter, the mixer, and the controllable gain transmitter amplifier are part of a transmit path common to the plurality of radio interfaces.

50. The direct-conversion transmitter of claim 45 , wherein the mixer is common to the plurality of radio interfaces.

51. The direct-conversion transmitter of claim 45 , further comprising a power amplifier, wherein the controllable low-pass filter, the mixer, the power amplifier, and the controllable gain transmitter amplifier are part of a transmit path common to the plurality of radio interfaces.

52. The direct-conversion transmitter of claim 45 , further comprising a digital-to-analog converter common to the plurality of radio interfaces of the direct-conversion transmitter and configured to generate the analog baseband transmission signal, wherein the digital-to-analog converter, the controllable low-pass filter, the mixer, and the controllable gain transmitter amplifier are part of a transmit path common to the plurality of radio interfaces.

53. The direct-conversion transmitter of claim 2 , further comprising a power amplifier configured to amplify the carrier-frequency signal amplified by the controllable gain transmitter amplifier, the power amplifier having a controllable operating frequency band set according to which one of the plurality of radio interfaces is selected.

54. The direct-conversion transmitter of claim 2 , further comprising a power amplifier, wherein the controllable low-pass filter, the mixer, the power amplifier, and the controllable gain transmitter amplifier are part of a transmit path common to the plurality of radio interfaces.

55. The direct-conversion transmitter of claim 2 , further comprising a bandpass filter, wherein the controllable low-pass filter, the controllable gain transmitter amplifier, and the bandpass filter are part of a transmit path common to the plurality of radio interfaces.

56. The direct-conversion transmitter of claim 2 , further comprising a digital-to-analog converter common to the plurality of radio interfaces of the direct-conversion transmitter and configured to generate the analog baseband transmission signal, wherein the digital-to-analog converter, the controllable low-pass filter, and the controllable gain transmitter amplifier are part of a transmit path common to the plurality of radio interfaces.

57. A transceiver configured to employ direct conversion in both the transmission and reception of RF signals associated with different radio interfaces of communication systems, comprising

means for generating a digital baseband quadrature signal on the basis of the information signal to be transmitted,

digital-to-analog converter means for converting the digital baseband transmission signal to analog,

synthesizer,

a controllable frequency divider for dividing a frequency of an output signal generated by the synthesizer to produce a TX mixing signal, wherein the number by which the frequency divider divides the synthesizer output signal depends on the selected transmit frequency band, so that the frequency corresponds to the selected transmission frequency, and wherein 90-degree phase-shifted components of the TX mixing signal are produced as quotients generated already in the frequency divider, wherein said frequency division is a division at least by two, so that a synthesizer operating frequency is used which is a multiple of the highest system frequency,

mixing means for producing a signal at a carrier frequency from the analog baseband transmission signal by means of the TX mixing signal,

characterised in that the transceiver further comprises

a low-pass filter means for filtering the analog baseband transmission signal, the cut-off frequency of the low-pass filter means being controllable so as to correspond to the specifications of the radio interface selected,

controllable gain transmitter amplifier configured to amplify a carrier frequency signal destined to be amplified by a power amplifier and transmitted by an antenna means,

and wherein in a direct conversion transmitter portion of the transceiver, the controllable gain transmit amplifier and the controllable low pass filter means are configured to process transmit signals associated with different radio interfaces.