Wireless communication apparatus

• US 20030147475A1
• Filed: 11/01/2002
• Published: 08/07/2003
• Est. Priority Date: 03/16/2001
• Status: Active Grant

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: Sasabata, Akihiro
• Granted Patent: US 7,120,202 B2
• Time in Patent Office: Days
• US Class Current: 375/308
• CPC Class Codes: H04L 27/0008 arrangements for allowing a transmitter or receiver to use more than one type of modulation negotiating modulation type for two-way transmission paths H04L5/1453

Abstract

In a wireless communication apparatus which has the functions of both ASK modulation and QPSK modulation, which can be manufactured at a low cost, and which is small in size, an output terminal (5D) of a QPSK modulator (5) is connected to a carrier wave input terminal (1A) of an ASK modulator (1) via a switch (15). Also, an antenna (4) is connected to an output terminal (1C) of the ASK modulator (1) via a switch (16). Furthermore, a mixer (13) is provided between the switches (15) and (16). The switch (15) connects the QPSK modulator (5) and the ASK modulator (1) at the time of a transmission, whereas it connects the QPSK modulator (5) and the mixer (13) at the time of a reception. The switch (16) connects the ASK modulator (1) and the antenna (4) at the time of a transmission, whereas it connects the antenna (4) and the mixer (13) at the time of a reception. Thus, at the time of a transmission, an ASK-modulated wave or a QPSK-modulated wave is output using the ASK modulator (1) and the QPSK modulator (5). At the time of a reception, a sine wave is output by the QPSK modulator (5) and a data signal is down-converted, detected, or demodulated by the mixer (13).

Claims

1. A wireless communication apparatus comprising:

an ASK modulator for ASK-modulating a carrier wave using a data signal; and

a QPSK modulator for QPSK-modulating a carrier wave using an I-signal and a Q-signal;

wherein an output terminal of said QPSK modulator is connected to a carrier wave input terminal of said ASK modulator.

2. A wireless communication apparatus according to claim 1, further comprising:

a mixer; and

a switch provided between said QPSK modulator and each of said mixer and said ASK modulator, said switch connecting said ASK modulator and said QPSK modulator at the time of a transmission, and connecting said mixer and said QPSK modulator at the time of a reception;

wherein said QPSK modulator outputs a sine wave as a carrier wave to said mixer at the time of a reception.

3. A wireless communication apparatus according to claim 1 or claim 2,

wherein when outputting a QPSK-modulated wave at the time of a transmission, said QPSK modulator QPSK-modulates a carrier wave using an I-signal and a Q-signal to output a QPSK-modulated wave, and said ASK modulator amplifies the QPSK-modulated wave by a constant gain, and

when outputting an ASK-modulated wave at the time of a transmission, said QPSK modulator outputs a sine wave, and said ASK modulator ASK-modulates the sine wave using a data signal.

4. A wireless communication apparatus according to claim 3,

wherein when outputting a QPSK-modulated wave at the time of a transmission, said QPSK modulator receives input of data signals respectively as an I-signal and a Q-signal and outputs a QPSK-modulated wave, and said ASK modulator receives input of a signal having a constant voltage as a data signal and amplifies the QPSK-modulated wave by a constant gain.

5. A wireless communication apparatus according to claim 3 or claim 4,

wherein when outputting an ASK-modulated wave at the time of a transmission, said QPSK modulator receives input of signals having the same fixed phases and fixed amplitudes respectively as an I-signal and a Q-signal and outputs a sine wave, and said ASK modulator receives input of a data signal and ASK-modulates the sine wave to output an ASK-modulated wave.

6. A wireless communication apparatus according to claim 3 or claim 4,

wherein when outputting an ASK-modulated wave at the time of a transmission, said QPSK modulator receives input of signals based on a QPSK data signal “

00”

as an I-signal and a Q-signal and performs a π

/4 shift QPSK operation to output a sine wave, and said ASK modulator receives input of a data signal and ASK-modulates the sine wave to output an ASK-modulated wave.

7. A wireless communication apparatus according to claim 6,

wherein said QPSK modulator receives input of a carrier wave having a frequency which is lower than a predetermined frequency by a transmission rate/4·

Hz and performs a π

/4 shift QPSK operation to output a sine wave having the predetermined frequency.

8. A wireless communication apparatus according to claim 1 or claim 2,

wherein when outputting a QPSK-modulated wave at the time of a transmission, said QPSK modulator QPSK-modulates a carrier wave using an I-signal and a Q-signal to output a QPSK-modulated wave, and said ASK modulator amplifies the QPSK-modulated wave by a constant gain, and

when outputting an ASK-modulated wave at the time of a transmission, said QPSK modulator receives input of data signals having the same fixed phases and amplitudes thereof changing identically in time respectively as an I-signal and a Q-signal and outputs an ASK-modulated wave, and said ASK modulator receives input of a signal having a constant voltage as a data signal and amplifies the ASK-modulated wave by a constant gain.

9. A wireless communication apparatus according to one of claims 1 to 8, further comprising an up-mixer for raising frequency, connected between said ASK modulator and said QPSK modulator.

10. A wireless communication apparatus according to one of claims 2 to 8,

wherein said ASK modulator, said mixer, and said switch are integrated as an RF block.