JP2003163645A - Radio communication equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide radio communication equipment by which an analog signal of sound, a picture, etc., is digitized without using compression and extension technique accompanying A/D conversion and transmission of high quality picture lawful to a radio method can be performed. <P>SOLUTION: In the case of transmitting the analog signal of sound, a picture, etc., it is first modulated by an analog modulator 13 (AM, FM, or PM), sampled next by an analog pulse modulator 14 (PAM, PWM, or PPM), thereafter converted to an analog pulse string, digitized in synchronism with a reference clock signal, modulated by a digital modulator 19 corresponding to wireless, and transmitted. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication device for transmitting and receiving information by analog communication by wireless communication.

[0002]

2. Description of the Related Art Wireless analog data communication
The M, FM and PM modulation methods are generally widely used for radios, televisions, commercial radios and the like. On the other hand, as the digital modulation method, ASK, FSK, and PSK modulation methods are used for telemeter, ETC, LAN, and the like.

In particular, analog signals such as stereo sound and images are once converted into digital signals and compressed,
It is widely used to use a decompression technique to reduce the data transmission rate and perform wireless communication.

On the other hand, according to the Radio Law in the 2.4 GHz band, the frequency occupied bandwidth per wave is 26 MHz or less, which is defined by the standard ARIB STD-T66, and transmission / reception is performed using a digital communication system. It is prescribed.

At present, as a method of transmitting analog signals such as stereo sound and images through a wireless line, it is widely practiced to use a spread spectrum communication method for communication.

In the first-generation satellite broadcasting system, FM is used for images, and modulation and demodulation is performed for sounds using the DPSK system, which is broadcast to the ground. That is, the communication system is configured by analog modulation / demodulation for images and digital modulation / demodulation for voice.

[0007]

According to the current Radio Law [standard ARIB STD-T66], it is permitted to directly transmit and receive voice and image signals by radio waves using an analog modulation method such as AM, FM and PM. Not not. Due to legal regulations,
Only digital modulation schemes are allowed.

Also, transmission and reception of analog signals, which are voice and image signals, by digital communication are restricted by the Radio Law because the occupied frequency bandwidth is wide, and A / D conversion and compression / expansion technology of analog signals is also required. Becomes essential, and the electronic circuit system including the modulation / demodulation circuit is complicated, leading to cost increase.

The present invention has been made in view of the above-mentioned problems, does not require complicated compression and expansion techniques, saves power, and has a frequency occupied bandwidth that complies with the Radio Law. It is an object of the present invention to provide a transmission / reception wireless communication device capable of transmitting a simple and high-quality image.

[0010]

As a method for modulating an analog signal which is a voice or image signal, a means for selecting one of analog modulation methods such as AM, FM, PM and a modulated analog modulated signal are used. Furthermore, analog pulse modulation [P
AM, PWM, PPM] and a means for synchronizing the analog pulse data signal with a certain reference synchronization clock signal, and the analog pulse data signal is digitally modulated [ASK, FSK, MSK,
BPSK, QPSK, QAM, OFDM], and a wireless communication device that performs transmission and reception after selecting one or two.

In the transmitting unit, the analog pulse-modulated analog pulse data signal is sampled based on the sampling theorem, and in the receiving unit, a wireless transmission / reception communication device capable of reproducing the analog pulse data signal from the demodulated analog pulse group is provided. To do.

[0012]

1 is a circuit block diagram showing an outline of a wireless communication apparatus according to an embodiment of the present invention. First, the main components will be described from the transmitting section. In the transmitter of the wireless communication device, analog signals, which are voice and image signals, are input to the individual input terminals of the voice signal and the image signal. However, the audio signal is a stereo signal, is input to the stereo modulator 11, and a stereo composite signal is obtained from the output. On the other hand, the image signal is amplified via the image amplifier 12. Next, an analog signal which is a sound or image signal is modulated by an analog modulator [AM, FM, PM] 13. In FIG. 1, PM modulation is shown. Further, the analog modulation signal is an analog pulse modulator [PAM, PWM, P
PM] 14 is converted into an analog pulse data signal and is synchronized with the clock signal of the transmission reference synchronization clock generator 15 via the transmission synchronization circuit 16 to form a digital signal.
FIG. 1 uses an analog pulse modulator based on PPM. Each digital signal which is an audio signal and an image signal is input to the audio low-pass filter 17 and the image low-pass filter 18, and each digital signal is a digital modulator [ASK, FSK, M
SK, BPSK, QPSK, QAM, OFDM] 19. In the case of the digital modulator 19 of FIG. 1, the QPS
This shows that the K modulation method was used. However, when the image signal and the audio signal are modulated by ASK, FSK or BPSK which is one of the digital modulators 19, a synthesizer of the audio signal and the image signal is required. Digital modulator 1
The digital modulation signal modulated by 9 is converted into the frequency converter 20.
After being frequency-converted into a quasi-microwave band via a high frequency power amplifier 21, the high frequency power amplifier 21 amplifies the power to a predetermined power level, and then radiates the free space through a bandpass filter 22 and a transmission antenna 23.

An analog signal which is a voice signal and an image signal is subjected to analog modulation, analog pulse modulation and digital modulation using a VHF band frequency in consideration of cost and power saving, and is frequency-converted in a quasi-microwave band before being transmitted. On the other hand, by using the analog pulse modulation method, A /
Simple digitization is possible without using complicated compression and decompression technology associated with D conversion. The reference synchronization clock generator 15 for transmission is also a PLL using a VCO with an analog circuit.
A simple and high-speed clock signal can be generated by designing with a circuit configuration. Regarding the digital modulator 19,
In FIG. 1, in the case of using QPSK, the frequency occupied bandwidth can be 1/2 of BPSK by inputting and modulating each digital signal of voice for I signal and image for Q signal.

Compared with a conventional radio communication device for transmitting voice and images by a spread spectrum communication system, the cost is small, the size is simple, the power is saved, and the radio wave method [standard ARI
According to B STD-T66], since it is an analog pulse signal, a faithful continuous moving image can be reproduced with high image quality including sound. Furthermore, if control of audio and image signals occurs, CP
By adding the U24 and the memory circuit 25, recording, transmission of still images and the like are possible.

Next, the receiving section of the main constituent elements in FIG. 1 will be described. For the transmitted digital modulation signal, either one of the diversity reception antennas 51a and 51b is switching-controlled by the CPU 62 and the memory circuit 63, is switched by the antenna switching switch 64, and is transmitted through the bandpass filter 52. After being input to the noise amplifier 53 and amplified, it is converted into a required intermediate frequency in the VHF band by the frequency converter 54. Further, after being amplified through the intermediate frequency amplifier 55, the QPSK demodulator 5
6 is input. Audio I / O composite signals are demodulated into I signals, and digital signals of images are demodulated into Q signals. Each of the I and Q signals is input to the analog pulse demodulator 57, and after demodulation, each digital signal is obtained as an analog pulse signal synchronized with the reference clock via the reception reference synchronization clock generator 58 and the reception synchronization circuit 59. To be However, the digital demodulator
When a demodulator such as SK, BPSK or FSK is used, voice. A filter or separator that separates the image signal is required. Further, the reception reference synchronization clock generator 58 is configured by the same design method as the transmission reference synchronization clock generator 15 of the transmitter. On the other hand, the analog pulse signal is demodulated into audio and image signals via an analog demodulator 60 [AM, FM, PM]. However, in FIG. 1, PM is selected and the audio stereo signal is reproduced via the stereo demodulator 61.

When control of voice and image signals occurs, recording is performed by adding a CPU 62 and a memory circuit 63.
It is also possible to play back still images, etc., and also control the space diversity antenna switching.

Although the present embodiment has been described based on the standard ARIB STD-T66 in the 2.4 GHz band,
5.1 GHz to 5.2 GHz band high-speed wireless LAN [MM
AC] and millimeter-wave band standards.

[0018]

As described above, according to the present invention, the following effects can be obtained. (1) By converting analog signals such as voice and images into analog pulse signals, digitalization is possible with a simple electronic circuit without using the compression / expansion technology that accompanies A / D conversion, leading to compact size and power saving. . (2) Space diversity is realized by antenna switching control using the CPU 62 and the memory circuit 63, and measures against multipath fading are taken. (3) By adding the CPU 62 and the memory circuit 63, it is possible to reproduce a recording, a still image and the like. (4) A linear high image quality peculiar to an analog signal can be obtained, and the occupied frequency bandwidth can be realized by a digital communication system in compliance with legal regulations. (5) By the QPSK modulation method, both voice and image signals can be transmitted within a frequency band within legal regulations.

From the above effects, it is simple and compact,
It is possible to provide a power-saving type transmission / reception wireless communication device for high-quality transmission.

[Brief description of drawings]

FIG. 1 is a circuit block diagram showing an outline of a wireless communication device according to an embodiment of the present invention.

[Explanation of symbols]

11: stereo modulator, 12: image amplifier, 13: analog modulator, 14: analog pulse modulator, 15: reference synchronization clock generator for transmission, 16: synchronization circuit for transmission, 1
7: low-pass filter for audio, 18: low-pass filter for image,
19: Digital modulator, 20: Frequency converter, 21: High frequency power amplifier, 22: Band filter, 23: Transmission antenna, 51a, 51b: Diversity receiving antenna, 52: Band filter, 53: High frequency low noise amplifier,
54: frequency converter, 55: intermediate frequency amplifier, 56:
QPSK demodulator, 57: analog pulse demodulator, 58:
Reference synchronization clock generator for reception, 59: synchronization circuit for reception, 60: analog demodulator PM, 61: stereo demodulator, 62: CPU, 63: memory circuit, 64: antenna changeover switch.

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) H04L 27/36 H04L 27/00 F

Claims (4)

[Claims] 1. In the case of a device for wirelessly transmitting audio and video, AM, FM, P as means for modulating an analog signal.
One of the analog modulations such as M is selected, and then the selected analog modulation signal is used as an analog pulse modulation means.
A transmission / reception wireless communication device characterized in that one of AM, PWM, and PPM is selected, sampled, converted into an analog pulse train, digitized in synchronization with a predetermined reference clock signal, and transmitted. 2. ASK and ASK as high frequency wireless digital modulation means after converting voice and image signals into analog pulse trains.
FSK, MSK, BPSK, QPSK, QAM, OFD
A transmission / reception wireless communication device characterized by selecting one or two of each digital modulation method by M or the like for communication. 3. Recording by adding a CPU and a memory circuit for all analog signals regardless of audio and image signals,
The transmission / reception wireless communication device according to claim 1, which is capable of transmitting still images and the like. 4. A receiving wireless communication device which adopts a space diversity technique as a measure against multipath fading and is capable of antenna switching by CPU and memory control.