JP2829029B2 - Broadband communication method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a frequency hopping broadband communication method.

[Conventional technology]

Conventionally, as a basic frequency hopping system, the document "Latest spread spectrum communication system"
There was one shown in Figure 2.12. FIG. 2 shows this conventional basic frequency hopping system, in which:
1 is a transmitter, 2 is a transmitting antenna, 3 is a radio wave propagation path, 4 is a receiving antenna, and 5 is a receiver.

FIG. 3 shows the frequency characteristics of each part in the conventional frequency hopping system. FIG. 3 (a) shows the transmission and reception antennas, FIG. 3 (b) shows the receiver, and FIG. 3 (c) shows the transmitter. FIG. 4D shows the frequency characteristics of the propagation path, and FIG. 4E shows the overall frequency characteristics of FIGS. 4A to 4D.

FIG. 4 shows the output of the broadband frequency hopping signal emitted from the transmitting antenna 2.

Next, the operation will be described. The output of the transmitter 1 has a frequency characteristic shown in FIG. The transmission output shown in FIG. 4 is emitted from the transmission antenna 2 and reaches the reception antenna 4 through the propagation path 3. The transmission loss frequency characteristics of the transmitting and receiving antennas are shown in FIG. 3 (a) in the form of a standing wave ratio and its conversion into dB. The level deviation of the transmitter output is at most 3 dB, and the level deviation of the antenna transmission loss is at most about 1 dB. On the other hand, the level deviation of the loss of the propagation path 3 is about 10 dB as shown in FIG. However, here, it was assumed that the fourth power law, that is, the rule that the propagation loss is proportional to the fourth power of the frequency, was followed.

The broadband frequency hopping signal that has arrived at the receiving antenna 4 is input to the receiver 5. The receiver 5 has a frequency characteristic shown in FIG. 3 (b) and has a level deviation of about 8 dB. FIG. 3 (e) shows the overall frequency characteristics including transmission and reception.

[Problems to be solved by the invention]

Since the conventional wideband communication device is configured as described above, a level deviation occurs due to the frequency as a whole, and at a frequency where the relative gain is low, a characteristic deterioration such that a signal cannot be detected due to a level fluctuation on the receiving side occurs. There was a point.

The present invention has been made in order to solve the problems of the conventional device as described above, and without complicating the device,
An object of the present invention is to obtain a broadband frequency communication method with less characteristic deterioration.

[Means for solving the problem]

A broadband communication method according to the present invention is a frequency hopping broadband communication method in which a frequency is switched momentarily to obtain a frequency characteristic of a radio wave propagation path between a transmitting side and a receiving side in advance, and Out of the transmitting antenna, the receiver on the receiving side and the receiving antenna, set a frequency characteristic of a part thereof, and based on the frequency characteristic of the part and the frequency characteristic of the propagation path, the frequency characteristic of the other part. By adjusting the frequency characteristics of the transmitter, the transmitting antenna, the receiver, and the receiving antenna, the overall frequency characteristics including the frequency characteristics of the propagation path are also flattened.

[Action]

In the present invention, the flattening of the frequency characteristics is realized by canceling the frequency characteristics of the transmitter, the transmitting / receiving antenna, and the receiver in consideration of the propagation path.

〔Example〕

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. First
FIG. 1 shows a broadband communication method according to an embodiment of the present invention. FIG. 1A shows the frequency characteristics of a transmitting and receiving antenna, FIG. 2B shows the frequency characteristics of a receiver, and FIG. FIG. 3 (d) shows the frequency characteristics of the
FIG. 7E shows the propagation loss of the propagation path when the power law is followed, and FIG.

The block configuration of the device used in the broadband communication method according to one embodiment of the present invention is the same as that of the conventional device shown in FIG. FIG. 6 shows a broadband frequency hopping signal output from the transmitting antenna 2.

Next, the operation will be described. The output of the transmitter 1 has a frequency characteristic shown in FIG. The transmission output shown in FIG. 6 is emitted from the transmission antenna 2 and reaches the reception antenna 4 through the propagation path 3. The broadband frequency hopping signal that has arrived at the receiving antenna 4 is input to the receiver 5. Sending
FIG. 1 (a) shows the frequency characteristics of the receiving antenna, and FIG. 1 (b) shows the frequency characteristics of the receiver.

As shown in FIG. 1 (a), the transmission / reception antenna's frequency characteristics are reduced in passband in a high frequency band, and the frequency characteristics of the receiver are increased in a high frequency band with a relative gain as shown in FIG. 1 (b). Take it high. Here, the frequency characteristics of the transmitter and the receiver are represented by relative gain (minus dB), and the frequency characteristics of the transmitting / receiving antenna and the propagation path are represented by pass loss and relative gain (minus dB), respectively. On the other hand, the frequency characteristics of the propagation path are obtained in advance as shown in FIG. 1 (d), and the frequency characteristics of the transmitting / receiving antenna and the frequency characteristics of the receiver are shown in FIG.
If it can be set as shown in (b), the frequency characteristics of the transmitter, the transmitting antenna, and the receiving antenna are adjusted to include the frequency characteristics of the propagation path by adjusting the frequency characteristics of the transmitter as shown in FIG. 1 (c). The overall frequency characteristic over the entire communication path can be flattened over a wide band as shown in FIG. Of course, if the frequency characteristics of the transmitting and receiving antennas and the frequency characteristics of the transmitter (FIGS. 1A and 1C) can be set,
The frequency characteristics of the receiver may be adjusted as shown in FIG. However, in the above embodiment, the overall frequency characteristic is flattened over a wide band as shown in FIG. 1 (e). However, as can be seen from comparison with the conventional FIG. While admitting that the loss will be larger than before,
The flattening of the overall frequency characteristic is realized by preventing the conventional extreme loss of the relative loss at f3 and f4.

Further, in the above embodiment, the transmission / reception antenna has a low pass loss in a high frequency range and the receiver has a high relative gain in a high frequency range. Although the transmission loss is low in the low frequency band, the transmission loss is high in the high frequency band, and the frequency characteristics of the receiver are such that the relative gain is high in the low frequency band and the relative gain is low in the high frequency band. The frequency characteristics of the transmitter may be adjusted so as to flatten the overall frequency characteristics over the range.

In the above embodiment, the frequency characteristic of the receiver is set to have a high relative gain in a high frequency range. However, as shown in FIG. 5, a plurality of receiving units may be provided in the receiver to perform band division. A broadband communication device with a small level deviation can be obtained.

〔The invention's effect〕

As described above, according to the broadband communication method according to the present invention, in the frequency hopping wideband communication method in which the frequency is switched momentarily to communicate, the frequency characteristic of the radio wave propagation path between the transmitting side and the receiving side is previously determined. The transmitter on the transmitting side, the transmitting antenna, the receiver on the receiving side and the receiving antenna, set a frequency characteristic for a part thereof, based on the frequency characteristic for the part and the frequency characteristic of the propagation path, By adjusting the frequency characteristics of the other parts, the transmitter, the transmitting antenna, the receiver and the receiving antenna to flatten the overall frequency characteristics including the frequency characteristics of the propagation path to the frequency characteristics of the receiving antenna. Therefore, there is an effect that a broadband communication method with less characteristic deterioration can be obtained without complicating the apparatus.

[Brief description of the drawings]

FIG. 1 is a diagram showing a broadband communication method according to an embodiment of the present invention. FIG. 1 (a) is a diagram showing frequency characteristics of a transmitting / receiving antenna, and FIG. 1 (b) is a frequency characteristic of a receiver. FIG. 1 (c) is a diagram showing a frequency characteristic of a transmitter, FIG. 1 (d) is a diagram showing a frequency characteristic of a propagation path, and FIG. 1 (e) is a diagram showing an entire frequency characteristic. It is. FIG. 2 is a diagram showing a conventional broadband communication device or a broadband communication device used in one embodiment of the present invention. FIG. 3 is a diagram showing a conventional broadband communication device. FIG. 3 (a) is a transmitting / receiving antenna. FIG. 3 (b) is a diagram showing the frequency characteristics of the receiver, FIG. 3 (c) is a diagram showing the frequency characteristics of the transmitter, and FIG. 3 (d) is the frequency of the propagation path. Diagram showing characteristics, third
FIG. 4 (e) shows the overall frequency characteristic, FIG. 4 shows the transmission antenna output wide band frequency hopping signal of the conventional wide band communication apparatus, and FIG. 5 shows the receiver according to another embodiment of the present invention. FIG. 6 is a diagram showing frequency characteristics, and FIG. 6 is a diagram showing a broadband frequency hopping signal of a transmitting antenna output according to an embodiment of the present invention. In the figure, 1 is a transmitter, 2 is a transmitting antenna, 3 is a propagation path, 4 is a receiving antenna, and 5 is a receiver. In the drawings, the same reference numerals indicate the same or corresponding parts.

Continuation of the front page (72) Inventor Masahiko Murakami 8-1-1 Tsukaguchi Honcho, Amagasaki-shi, Hyogo Mitsubishi Electric Corporation Communication Equipment Works (56) References JP-A-63-138824 (JP, A) JP-A Sho 60-197040 (JP, A)

Claims (1)

(57) [Claims] 1. A frequency hopping broadband communication method for performing communication by switching a frequency every moment, wherein a frequency characteristic of a radio wave propagation path between a transmission side and a reception side is obtained in advance, and the transmission side transmitter, transmission antenna, Setting a frequency characteristic of a part of the receiver and the receiving antenna on the receiving side, and adjusting a frequency characteristic of the other part based on the frequency characteristic of the part and the frequency characteristic of the propagation path; Wherein the frequency characteristics of the transmitter, the transmitting antenna, the receiver, and the receiving antenna are flattened as a whole frequency characteristic including a frequency characteristic of the propagation path.