JPS63199527A - Communication equipment for high speed mobile body - Google Patents

Abstract

PURPOSE:To simplify the circuit constitution of a receiver and to attain the inexpensive equipment by shifting in advance a transmission frequency of a transmitter by a frequency corresponding to an estimated Doppler shift of a communication wave. CONSTITUTION:A data inputted from a data input terminal 1 is converted into a radio modulation signal by a modulator 2. On the other hand, Doppler information obtained from an object tracing radar or the like from a Doppler information input terminal 9 is inputted to a frequency shift quantity control circuit 8. The synthesized frequency to be shifted is mixed with a radio modulation signal from the modulator 2 by a mixer 3 and converted into a high frequency signal. The Doppler shift is cancelled in the receiver. Thus, it is possible to process the communication wave from the high speed mobile body with high accuracy while employing the conventional constitution for the receiver.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a communication device for a high-speed moving body.

[Conventional technology]

FIG. 3 shows a conventional mobile communication device. In the figure,
1 is a data input terminal, 2 is a modulator, 3 is a mixer, 4 is a bandpass filter, 5 is a power amplifier, 6 is a transmitting antenna, and 7 is a local oscillator. In addition, 10 is a playback data output terminal, 1
1 is a demodulator, 12 is a reception IP filter, 13 is a mixer,
14 is a receiving 32 circuit, 15 is a receiving antenna, and 16 is a local oscillator.

Next, the operation will be explained.

In the transmitter, the data entered manually from the data input terminal l is
The modulator 2 converts the signal into a radio modulated signal.

The radio modulated signal is mixed in the mixer 3 with the signal synthesized by the local oscillator 7, thereby converting it into a high frequency signal. After high frequency components are removed from the high frequency signal by a bandpass filter 4, it is amplified by a power amplifier 5, and radio waves are emitted from a transmitting antenna 6.

On the other hand, in the receiver, the received signal received by the receiving antenna 15 is amplified and unnecessary wave removed by the receiving RF circuit 14, and then mixed with the signal synthesized by the local oscillator 16 in the mixer 13. , converted to an IF frequency.

After unnecessary components are removed by the IF multiplied signal reception IF filter 12, the signal is demodulated by the demodulator 11. The demodulated playback data is output from the playback data output terminal 10.

[Problem that the invention seeks to solve]

Since the conventional mobile communication device is configured as described above, the transmission wave F1 emitted from the transmitter is frequency-shifted by the Doppler shift ΔF due to the relative movement of the transmitter and receiver, and the receiver receives Fl- It is received as a received wave of ΔF (when it is far away). Therefore, in the receiver, the frequency shift of ΔF directly affects the operating offset amount of the demodulator, so there are problems such as it is difficult to realize a demodulator in high-speed moving objects where ΔF is large, that is, the Doppler shift is large. .

This invention was made to solve the above-mentioned problems, and it can be used for high-speed moving objects that can handle Doppler shifts ranging from small to extremely large, while maintaining the same simple configuration as the receiver. The purpose is to obtain communication equipment.

[Means for solving problems]

The communication device for a high-speed moving object according to the present invention predicts the amount of Doppler shift of a communication wave based on Doppler information accompanying the movement of a high-speed moving object obtained from a barmark tracking radar, etc., and It applies a frequency shift in the opposite direction by the amount of the Doppler shift, and controls the signal received by the receiver so that the Doppler shift is always canceled.

[Effect]

In this invention, the frequency is shifted in the opposite direction by the Doppler shift expected on the transmitter side and then transmitted. As a result, the Doppler shift is canceled and input on the receiver side, so that even a high-speed moving body with a large Doppler shift can receive it with a receiver similar to the conventional one.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

In FIG. 1, the same symbols as in FIG. 3 are the same. 9 is a Doppler information input terminal, and 8 is a frequency shift amount control circuit.

Next, the operation will be explained.

First, on the transmitting side, data input from a data input terminal 1 is converted into a radio modulated signal by a modulator 2. On the other hand, from the Doppler information input terminal 9, the Doppler information obtained from the target tracking radar etc. is frequency shifted)! It is input to the control circuit 8. In this control circuit 8, the amount of Doppler shift of the communication wave is predicted from the above-mentioned Doppler information, and the amount control signal for one frequency shift is generated to generate a control signal that gives the communication wave a frequency shift in the opposite direction by the amount of the shift. A frequency shift is given to the synthesized frequency of the local oscillator 7.

The synthesized frequency frequency-shifted in this manner is mixed with the wireless modulation signal from the modulator 2 in the mixer 7, and converted into a high frequency signal. Unnecessary wave components are removed from this high frequency signal by a bandpass filter 4, amplified by a power amplifier 5, and radio waves are emitted from a transmitting antenna 6.

Operation at the receiver is similar to the conventional system.

However, since the transmitted wave emitted from the transmitter is F1 + ΔF with a frequency shift of ΔF, the received wave Doppler-shifted due to the relative movement of the transmitter and receiver becomes (Fl + ΔF) - ΔF-F 1, and the Doppler shift is It will be considered cancelled. Therefore, in this embodiment, it is possible to process communication waves from a high-speed moving body with high precision while keeping the receiver configuration as is.

In the above embodiment, the frequency shift circuit of the transmitter shifts the frequency of the local oscillator, but as shown in FIG. 2, the frequency shift circuit shifts the offset frequency of the modulator 2. You can also do this.

〔Effect of the invention〕

As described above, according to the present invention, the frequency of the transmitter is shifted in advance by the expected Doppler shift of communication waves, so that it can be used even when processing communication waves from high-speed moving objects. This has the effect of simplifying the circuit configuration of the receiver, making the device inexpensive, and highly accurate and stable in operation.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a communication device for a high-speed moving body according to one embodiment of the present invention, and FIG. 2 is a diagram showing another embodiment of the present invention.
FIG. 3 is a diagram showing the configuration of a conventional mobile communication device. l...Data input terminal, 2...Modulator, 3...Mixer, 4...Band filter, 5...Power amplifier, 6
... Transmitting antenna, 7... Local oscillator, 8... Frequency shift amount control circuit, 9... Donpra information input terminal,
lO... Reproduction data input terminal, 11... Demodulator, 1
2... Reception IF filter, 13... Mixer, 14.
...Receiving RF circuit, 15...Receiving antenna, 16...
Local oscillator. Note that the same reference numerals in the figures indicate the same or equivalent parts. Figure 2

Claims (3)

[Claims] (1) In communication equipment for high-speed moving objects where large Doppler shifts occur in communication waves, the amount of Doppler shift in communication waves is predicted based on Doppler information accompanying the movement of high-speed moving objects obtained from target tracking radar, etc. 1. A communication device for a high-speed moving body, comprising frequency shift amount control means for generating a control signal for giving a frequency shift in the opposite direction by a Doppler shift amount to communication waves in advance. (2) The communication device for a high-speed mobile object according to claim 1, wherein the control signal applies a frequency shift to the synthesized frequency of the transmitting local oscillator. (3) The communication device for a high-speed mobile object according to claim 1, wherein the control signal applies a frequency shift to the offset frequency of the modulator.