Wireless communications equipment

• US 20030153294A1
• Filed: 10/23/2002
• Published: 08/14/2003
• Est. Priority Date: 02/14/2002
• Status: Active Grant

• Current Assignee: Hitachi Kokusai Electric Incorporated (Hitachi, Ltd.)
• Original Assignee: Hitachi Kokusai Electric Incorporated (Hitachi, Ltd.)
• Inventors: Hata, Yoshiyuki
• Granted Patent: US 6,917,803 B2
• Time in Patent Office: Days
• US Class Current: 455/302
• CPC Class Codes: H04B 1/0003 Software-defined radio [SDR] systems, i.e. systems wherein components typically implemented in hardware, e.g. filters or modulators/demodulators, are implented using software, e.g. by involving an AD or DA conversion stage such that at least part of the signal processing is performed in the digital domain digital baseband systems H04L25/00; digital modulation/demodulation H04L27/00; CDMA H04B1/707; TDMA H04B7/2643; image transmission H04N5/00
• CPC Class Codes: H04B 1/0007 wherein the AD/DA conversion occurs at radiofrequency or intermediate frequency stage
• CPC Class Codes: H04B 1/005 adapting radio receivers, transmitters andtransceivers for operation on two or more bands, i.e. frequency ranges
• CPC Class Codes: H04B 1/0057 using diplexing or multiplexing filters for selecting the desired band
• CPC Class Codes: H04B 1/006 using switches for selecting the desired band H04B1/0057 takes precedence
• CPC Class Codes: H04B 1/28 the receiver comprising at least one semiconductor device having three or more electrodes
• CPC Class Codes: H04B 1/403 using the same oscillator for generating both the transmitter frequency and the receiver local oscillator frequency

Abstract

Wireless communications equipment that wirelessly communicates signals on a plurality of communication frequencies includes: a baseband frequency-side frequency conversion means that performs conversion between baseband signals on the baseband frequency and signals on a stipulated frequency higher than the baseband frequency and different from the intermediate frequency, an intermediate frequency-side frequency conversion means that performs conversion between the signals on said stipulated frequency and intermediate frequency signals on a plurality of intermediate frequencies corresponding to a plurality of communication frequencies, and an unwanted frequency signal component removal means that removes signal components of unwanted frequencies from the signals on said stipulated frequency. Thus, it is possible to share the components used for the removal of unwanted frequency signal components for the intermediate frequency signals of a plurality of intermediate frequencies, and thus the cost and unit size can be reduced.

Claims

1. Wireless communications equipment that wirelessly communicates signals on a plurality of communication frequencies, comprising:

baseband frequency-side frequency conversion means that performs conversion between baseband signals on the baseband frequency and signals on a stipulated frequency higher than the baseband frequency and different from the intermediate frequency;

intermediate frequency-side frequency conversion means that performs conversion between the signals on said stipulated frequency and intermediate frequency signals on a plurality of intermediate frequencies corresponding to a plurality of communication frequencies; and

unwanted frequency signal component removal means that removes signal components of unwanted frequencies from the signals on said stipulated frequency.

2. The wireless communications equipment according to claim 1, wherein:

the baseband frequency-side frequency conversion means in the sending process and the intermediate frequency-side frequency conversion means in the receiving process are constituted using a common first mixer;

the intermediate frequency-side frequency conversion means in the sending process and the baseband frequency-side frequency conversion means in the receiving process are constituted using a common second mixer; and

the unwanted frequency signal component removal means in the sending process and the unwanted frequency signal component removal means in the receiving process are constituted using a common filter,

further comprising;

sending/receiving switching means that performs switching between sending and receiving in time division, wherein;

when switched to the sending process by the sending/receiving switching means, the first mixer is used to convert the baseband signals to signals on said stipulated frequency, the filter is used to remove from said converted signals those signal components on unwanted frequencies, and the second mixer is used to convert said cleaned signals to intermediate frequency signals on an intermediate frequency subject to sending among the plurality of intermediate frequencies, and

when switched to the receiving process by the sending/receiving switching means, the first mixer is used to convert the intermediate frequency signals received on an intermediate frequency among the plurality of intermediate frequencies to signals on said stipulated frequency, the filter is used to remove from said converted signals those signal components on unwanted frequencies, and the second mixer is used to convert said cleaned signals to baseband signals.

3. The wireless communications equipment according to claim 2, further comprising:

a matching circuit for sending that achieves matching with the circuit for sending connected to the mixer and a matching circuit for receiving that achieves matching with the circuit for receiving connected to the mixer is provided on at least one of the first mixer and the second mixer.

4. The wireless communications equipment according to claim 1, further comprising:

a signal processor that performs the processing of the baseband signal;

a first filter that performs the filtering of the baseband signal input from the signal processor;

a first switch that connects the first filter to the first mixer during sending and connects the first amplifier to the first mixer during receiving;

a first PLL that supplies a local signal to the first mixer;

a first mixer that converts the filtered baseband signal input from the first filter via the first switch or the amplified intermediate frequency signal input from the first amplifier via the first switch to a signal on the stipulated frequency;

a second amplifier that amplifies said frequency-converted signal;

a second filter that performs the filtering of the amplified signal;

a second PLL that supplies a local signal for the second mixer;

a second mixer that converts said filtered signal to an intermediate frequency signal during sending and to a baseband signal during receiving;

a second switch that connects a third filter to the second mixer during sending and connects a fourth filter to the second mixer during receiving;

a third filter that performs the filtering of the intermediate frequency signal input from the second mixer via the second switch;

a transmitter power controller that controls the transmitter power of said filtered intermediate frequency signal;

a third switch that connects the transmitter power controller to the IF signal input/output pin during sending and connects the first amplifier to the IF signal input/output pin during receiving;

an IF signal input/output pin that outputs to the outside the intermediate frequency signal input from the transmitter power controller via the third switch and outputs to the first amplifier via the third switch the intermediate frequency signal input from outside;

a first amplifier that amplifies the intermediate frequency signal input from the IF signal input/output pin via the third switch;

a fourth filter that performs the filtering of the baseband signal input from the second mixer via the second switch; and

a third amplifier that controls the power of the filtered baseband signal and outputs said power-controlled baseband signal to the signal processor.

5. The wireless communications equipment according to claim 1, wherein:

in the sending process, the baseband frequency-side frequency conversion means converts the baseband signals to signals on said stipulated frequency, the unwanted frequency signal component removal means removes signal components of unwanted frequencies from the converted signals on said stipulated frequency, and the intermediate frequency-side frequency conversion means converts said cleaned signals to intermediate frequency signals.

6. The wireless communications equipment according to claim 1, wherein:

in the receiving process, the intermediate frequency-side frequency conversion means converts the intermediate frequency signals to signals on said stipulated frequency, the unwanted frequency signal component removal means removes signal components of unwanted frequencies from the converted signals on said stipulated frequency, and the baseband frequency-side frequency conversion means converts said cleaned signals to baseband signals.

7. The wireless communications equipment according to claim 1, wherein:

the smallest frequency within the plurality of intermediate frequencies is larger than the local frequency corresponding to the largest frequency,

as the unwanted frequency signal component removal means, a narrowband SAW filter is used to extract signals of said stipulated frequency, and

a broadband BPF filter is used to extract signals of frequencies from said smallest frequency to said largest frequency.

8. The wireless communications equipment according to claim 1, wherein:

the smallest frequency within the plurality of intermediate frequencies is larger than the baseband frequency, and the largest frequency is smaller than the local frequency corresponding to said smallest frequency,

as the unwanted frequency signal component removal means, a narrowband SAW filter is used to extract signals of said stipulated frequency, and

a broadband BPF filter is used to extract signals of frequencies from said smallest frequency to said largest frequency.

9. The wireless communications equipment according to claim 3, further comprising:

a sending circuit-side isolation assurance means for assuring isolation provided on the circuit for sending connected to the mixer provided on at least one of the first mixer and the second mixer, and a receiving circuit-side isolation assurance means for assuring isolation provided on the circuit for receiving connected to the mixer.

10. A FWA system constituting an indoor unit and outdoor unit connected via a coaxial cable and provided with a communications unit that communicates signals on a plurality of communication frequencies, wherein:

the indoor unit constituting the communications unit comprises;

baseband frequency-side frequency conversion means that performs conversion between baseband signals on the baseband frequency and signals on a stipulated frequency higher than the baseband frequency and different from the intermediate frequency, intermediate frequency-side frequency conversion means that performs conversion between the signals on said stipulated frequency and intermediate frequency signals on a plurality of intermediate frequencies corresponding to a plurality of communication frequencies, and unwanted frequency signal component removal means that removes signal components of unwanted frequencies from the signals on said stipulated frequency, and

in the communications unit, in the sending process, the indoor unit converts the baseband signals to intermediate frequency signals and sends the intermediate frequency signals to the outdoor unit via a coaxial cable, and the outdoor unit receives the intermediate frequency signals and converts the intermediate frequency signals to radio frequency signals and wirelessly transmits the radio frequency signals, and

in the communications unit, in the receiving process, the outdoor unit converts received radio frequency signals to intermediate frequency signals and sends the intermediate frequency signals to the indoor unit via a coaxial cable, and the indoor unit receives the intermediate frequency signals and converts the intermediate frequency signals to baseband signals.

11. The FWA system according to claim 10, wherein:

in the indoor unit constituting the communications unit, the baseband frequency-side frequency conversion means in the sending process and the intermediate frequency-side frequency conversion means in the receiving process are constituted using a common first mixer;

the intermediate frequency-side frequency conversion means in the sending process and the baseband frequency-side frequency conversion means in the receiving process are constituted using a common second mixer; and

the unwanted frequency signal component removal means in the sending process and the unwanted frequency signal component removal means in the receiving process are constituted using a common filter,

further comprising;

sending/receiving switching means that performs switching between sending and receiving in time division, wherein;

when switched to the sending process by the sending/receiving switching means, the first mixer is used to convert the baseband signals to signals on said stipulated frequency, the filter is used to remove from said converted signals those signal components on unwanted frequencies, and the second mixer is used to convert said cleaned signals to intermediate frequency signals on an intermediate frequency subject to sending among the plurality of intermediate frequencies, and

when switched to the receiving process by the sending/receiving switching means, the first mixer is used to convert the intermediate frequency signals received on an intermediate frequency among the plurality of intermediate frequencies to signals on said stipulated frequency, the filter is used to remove from said converted signals those signal components on unwanted frequencies, and the second mixer is used to convert said cleaned signals to baseband signals.

12. The FWA system according to claim 11, wherein:

in the indoor unit constituting the communications unit, a matching circuit for sending that achieves matching with the circuit for sending connected to the mixer and a matching circuit for receiving that achieves matching with the circuit for receiving connected to the mixer is provided on at least one of the first mixer and the second mixer.

13. The FWA system according to claim 10, wherein:

the indoor unit constituting the communications unit comprises;

a signal processor that performs the processing of the baseband signal;

a first filter that performs the filtering of the baseband signal input from the signal processor;

a first switch that connects the first filter to the first mixer during sending and connects the first amplifier to the first mixer during receiving;

a first PLL that supplies a local signal to the first mixer;

a first mixer that converts the filtered baseband signal input from the first filter via the first switch or the amplified intermediate frequency signal input from the first amplifier via the first switch to a signal on the stipulated frequency;

a second amplifier that amplifies said frequency-converted signal;

a second filter that performs the filtering of the amplified signal;

a second PLL that supplies a local signal for the second mixer;

a second mixer that converts said filtered signal to an intermediate frequency signal during sending and to a baseband signal during receiving;

a second switch that connects a third filter to the second mixer during sending and connects a fourth filter to the second mixer during receiving;

a third filter that performs the filtering of the intermediate frequency signal input from the second mixer via the second switch;

a transmitter power controller that controls the transmitter power of said filtered intermediate frequency signal;

a third switch that connects the transmitter power controller to the IF signal input/output pin during sending and connects the first amplifier to the IF signal input/output pin during receiving;

an IF signal input/output pin that outputs to the outside the intermediate frequency signal input from the transmitter power controller via the third switch and outputs to the first amplifier via the third switch the intermediate frequency signal input from outside;

a first amplifier that amplifies the intermediate frequency signal input from the IF signal input/output pin via the third switch;

a fourth filter that performs the filtering of the baseband signal input from the second mixer via the second switch; and

a third amplifier that controls the power of the filtered baseband signal and outputs said power-controlled baseband signal to the signal processor.

14. The FWA system according to claim 10, wherein:

in the indoor unit constituting the communications unit, in the sending process, the baseband frequency-side frequency conversion means converts the baseband signals to signals on said stipulated frequency, the unwanted frequency signal component removal means removes signal components of unwanted frequencies from the converted signals on said stipulated frequency, and the intermediate frequency-side frequency conversion means converts said cleaned signals to intermediate frequency signals.

15. The FWA system according to claim 10, wherein:

in the indoor unit constituting the communications unit, in the receiving process, the intermediate frequency-side frequency conversion means converts the intermediate frequency signals to signals on said stipulated frequency, the unwanted frequency signal component removal means removes signal components of unwanted frequencies from the converted signals on said stipulated frequency, and the baseband frequency-side frequency conversion means converts said cleaned signals to baseband signals.

16. The FWA system according to claim 10, wherein:

in the indoor unit constituting the communications unit, the smallest frequency within the plurality of intermediate frequencies is larger than the local frequency corresponding to the largest frequency,

as the unwanted frequency signal component removal means, a narrowband SAW filter is used to extract signals of said stipulated frequency, and

a broadband BPF filter is used to extract signals of frequencies from said smallest frequency to said largest frequency.

17. The FWA system according to claim 10, wherein:

in the indoor unit constituting the communications unit, the smallest frequency within the plurality of intermediate frequencies is larger than the baseband frequency, and the largest frequency is smaller than the local frequency corresponding to said smallest frequency,

as the unwanted frequency signal component removal means, a narrowband SAW filter is used to extract signals of said stipulated frequency, and

a broadband BPF filter is used to extract signals of frequencies from said smallest frequency to said largest frequency.

18. The FWA system according to claim 12, wherein:

the indoor unit constituting the communications unit comprises;

a sending circuit-side isolation assurance means for assuring isolation provided on the circuit for sending connected to the mixer provided on at least one of the first mixer and the second miser, and a receiving circuit-side isolation assurance means for assuring isolation provided on the circuit for receiving connected to the mixer.