JPH0722279B2 - Receiver - Google Patents

Description

TECHNICAL FIELD The present invention relates to a frequency hopping type receiver,
Particularly, to obtain a receiver having excellent anti-interference performance [Prior Art] As a conventional device of this type, there is a device shown in Fig. 2 and 12 of "Latest spread spectrum communication system" (Jatech Publishing Co., Ltd.). This is shown in FIG. In the figure, 1 is a high frequency band filter, 2 is a high frequency amplifier for amplifying the output of the high frequency band filter 1, 5 is a mixer for mixing the output of the high frequency amplifier 2 and the output of a local oscillator 8 described later, 6 Is an intermediate frequency amplifier for filtering and amplifying the output of the mixer 5, 7 is a demodulator, 8 is a local oscillator, 9 is a hopping pattern generator for controlling the local oscillator 8, 10 is an antenna, and 11 is an output of the intermediate frequency amplifier 6. Is a level determiner, and 12 is a counter for controlling the local oscillator 8.

FIG. 5 is an example of the frequency hopping high frequency input when there is no interference. That is, this corresponds to an example of frequency hopping of the local oscillator 8. 6 and 7 show an example of the output of the local oscillator 8 controlled by the counter 12.

Next, the operation will be described. The reception input to the antenna 10 is suppressed by the high frequency band filter 1 to suppress unnecessary waves, amplified by the high frequency amplifier 2, and supplied to the mixer 5. Mixer 5
The other input to is the output of the local oscillator 8, which is hopped by the digital output of the hopping pattern generator 9 at a frequency separated from the input of the antenna 10 by an intermediate frequency difference. When the input to the antenna 10 and the output of the local oscillator 8 are synchronously hopping, the intermediate frequency amplifier 6 always amplifies the signal. The demodulator 7 detects and demodulates the signal to obtain information.

The output of the high frequency amplifier 2 is also input to the other mixer 5 and mixed with the output of the local oscillator 8. The local oscillator 8 in this case is controlled by the digital output of the counter 12 and sweeps the hopping channels sequentially. Then, when the difference between the sweep frequency and the input frequency matches the intermediate frequency, the intermediate frequency amplifier 6 amplifies the signal. The determiner 11 can detect the amplified intermediate frequency level, determine a wave other than the desired channel as an interfering wave, and know the interfering channel.

As shown in FIG. 6, if the switching speed of the local oscillator 8 controlled by the counter 12 is the same as that of the local oscillator 8 controlled by the hopping pattern generator 9 for information demodulation, it is necessary to detect the interference wave. For n-channel hopping, it takes a maximum of nT (T is one hop time). Further, as shown in FIG. 7, if the switching speed of the local oscillator 8 controlled by the counter 12 is increased, the interference detection time can be shortened, but the device becomes large.

[Problems to be solved by the invention]

Since the conventional receiving apparatus is configured as described above, in order to detect the interference wave, in addition to the local oscillator 8 (frequency synthesizer) controlled by the hopping pattern generator 9 for information demodulation, the interference wave detection is performed. Since the local oscillator 8 controlled by the counter 12 is required, the device becomes large and the circuit becomes complicated.

The present invention has been made in order to solve the above problems, and an object thereof is to provide a filter bank in a high frequency amplifier as a means for detecting an interfering wave and obtain a small and simple receiving device.

[Means for solving problems]

A receiving device according to the present invention is a frequency hopping receiving device that communicates by switching frequencies every moment,
A plurality of high-frequency band pass filters for filtering high-frequency input signals from the antenna, each having a different pass band, and a filter bank including a plurality of high-frequency amplifiers provided corresponding to the respective high-frequency band pass filters, , A level detector for detecting the output level of each of the high-frequency amplifiers, a hopping pattern generator for generating a hopping pattern, and a plurality of outputs from the level detector are switched and selected according to the hopping pattern to select a desired channel. A switch that outputs the received wave to one input of a mixer that configures a reception demodulation system in the subsequent stage, and outputs a signal of a predetermined level or higher detected by the level detector to the interfering wave detection system, and the hopping pattern. The signal hopped at a frequency separated by an intermediate frequency from the received wave of the desired channel is controlled by A local oscillator that outputs to the other input of the multiplexer, and a determiner that determines a received wave other than the desired channel output from the switch as an interfering channel. According to the present invention, because of the above configuration, it is possible to accurately detect an interfering wave without separately providing a counter for detecting the interfering wave and to demodulate only the desired wave without being affected by the interfering wave. It is possible to improve the interference wave performance and downsize the device. Further, by realizing the filter bank with, for example, a SAW (surface acoustic wave) element, the device can be further downsized.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, 1a to 1n are high frequency band filters of the filter bank configured by surface acoustic wave elements, for filtering signals from the antenna 10, and 2a to 2n are high frequency band filters 1a to 1n. High frequency amplifier for amplifying output, 3 is high frequency amplifiers 2a to 2n
Level detector for removing noise waves by comparing the output of the filter with a predetermined level, 4 is a switch for switching the output of the filter bank according to hopping control, and 5 is a switch 4
A mixer that mixes the signal switched by and the output of the local oscillator 8, 6 is an intermediate frequency amplifier that filters and amplifies the output of the mixer 5, 7 is a demodulator, 8 is a local oscillator, and 9 is a local oscillator 8. Controlling hopping pattern generator, 10 antenna,
Reference numeral 11 is a discriminator for discriminating a wave other than the desired channel from the output of the level detector 3 as an interfering wave, and 13 is a filter bank including high frequency filters 1a to 1n and high frequency amplifiers 2a to 2n.

FIG. 2 shows the filtering characteristics of the filters 1a to 1n. Further, FIG. 3 shows an example of the frequency hopping high frequency input when the disturbing wave exists in the f6 channel, and FIG. 5 shows an example of the frequency hopping high frequency input when the disturbing wave does not exist.

Next, the operation will be described. The input to the antenna 10 enters the filter bank 13 and each of the filters 1a to 1n and the high frequency amplifier 2a.
It is filtered and amplified by ~ 2n. The outputs of the respective high frequency amplifiers 2a to 2n are supplied to the level detector 3, which detects and stores the output levels of the respective high frequency amplifiers 2a to 2n at any time. Then, the switching device 4 selects a desired high-frequency signal by the switching signal of the hopping pattern generator 9 as the information demodulation signal, and supplies this signal to the mixer 5. The other input to the mixer 5 is the output of the local oscillator 8, which is hopped by the digital output of the hopping pattern generator 9 at a frequency separated from the high frequency signal by an intermediate frequency difference. Switch 4
When the high-frequency signal switched and selected in step 1 and the output of the local oscillator 8 are synchronously hopping, the intermediate frequency amplifier 6 constantly amplifies the signal. The demodulator 7 detects and demodulates the signal to obtain information.

On the other hand, regarding the detection of the interfering wave, each signal detected by the level detector 3 is supplied to the decision unit 11 via the switching unit 4. When a level exists in a channel (corresponding to the filter banks a to n) other than the desired high frequency signal in the decision unit 11, that is, when a level exists in a channel other than the predetermined channel provided by the hopping pattern generator 9, It is assumed that the channel is disturbing, and this is output as disturbing wave data. It should be noted that the decision unit 11 may make a decision by observing the detected channel information of a predetermined level temporally. That is, as is clear from FIG. 3, the interference wave is detected in the f6 channel continuously in time, so by observing this, the interference wave channel can be determined without the information of the hopping pattern. Becomes

In the above embodiment, the control signal of the hopping pattern generator 9 is used for controlling the level detector and the switching device.
As shown in FIG. 8, a high-speed sampling clock generator 14 may be newly provided, and the output thereof may control the level detection and switching device. By doing so, it is possible to easily realize high-speed detection of the interfering wave as shown in FIG. Further, in the above-described embodiment, the interference wave is CW as shown in FIG. 3, but it may be a time-varying interference such as follow jam, sweep, barrage, etc., and the same effect as in the above-mentioned embodiment is obtained. .

〔The invention's effect〕

As described above, according to the present invention, in a frequency hopping type receiver that communicates by switching frequencies every moment, different pass bands are set, and a plurality of high frequency band filters for filtering a high frequency input signal from the antenna are set. Wave instrument,
And a filter bank composed of a plurality of high-frequency amplifiers provided corresponding to each high-frequency band filter, a level detector for detecting an output level of each high-frequency amplifier, and a hopping pattern generator for generating a hopping pattern. , A plurality of outputs from the level detector are switched and selected according to the hopping pattern, and a received wave of a desired channel is output to one input of a mixer forming a reception demodulation system of a subsequent stage, and the level detector is also output. A switcher that outputs a signal of a predetermined level or higher detected by the interfering wave detection system, and a signal that is controlled by the hopping pattern and hops at a frequency separated from the received wave of the desired channel by an intermediate frequency of the mixer. The local oscillator that outputs to the other input, and the received wave other than the desired channel that is output from the switch Since the determination device for determining the interference channel is provided, it is possible to accurately detect the interference wave without separately providing a counter for detecting the interference wave and to demodulate only the desired wave without being affected by the interference wave. As a result, there is an effect that it is possible to obtain a small-sized and inexpensive receiving device as well as having excellent anti-interference performance.

[Brief description of drawings]

FIG. 1 is a block diagram of a receiver according to an embodiment of the present invention,
FIG. 2 is a diagram showing a filtering characteristic of each filter of the filter block in the apparatus, FIG. 3 is a diagram showing an example of frequency hopping high frequency input when an interfering wave is present, and FIG. FIG. 5 is a diagram showing a receiving device, FIG. 5 is a diagram showing an example of frequency hopping high frequency input when there is no interference wave, FIG. 6 is a diagram showing an output of a local oscillator for interference detection, and FIG. FIG. 8 is a diagram showing an output obtained by switching the local oscillator for use at high speed, and FIG. 8 is a diagram showing another embodiment of the present invention. 1a to 1n ... high frequency band filter, 2a to 2n ... high frequency amplifier, 3 ... level detector, 4 ... switcher, 5 ... mixer, 6 ... intermediate frequency amplifier, 7 ... demodulator , 8: local oscillator, 9: hopping pattern generator, 10: antenna, 11: decision device, 13: filter bank, 14: high-speed sampling clock generator. The same reference numerals in the drawings indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A frequency hopping type receiving apparatus for communicating by switching frequencies every moment, and a plurality of high-frequency band pass filters each having a different pass band set and filtering a high-frequency input signal from an antenna, and each of these. A filter bank composed of a plurality of high-frequency amplifiers provided corresponding to the high-frequency band filter, a level detector that detects the output level of each high-frequency amplifier, a hopping pattern generator that generates a hopping pattern, and the level A plurality of outputs from the detector are switched and selected according to the hopping pattern, and the reception wave of the desired channel is output to one input of the mixer that constitutes the reception demodulation system of the subsequent stage, and is detected by the level detector. The switching device that outputs a signal of a predetermined level or higher to the interfering wave detection system, and the hopping pattern described above A local oscillator that outputs to the other input of the mixer a signal that hops at a frequency separated from the received wave of the desired channel by an intermediate frequency, and a received wave of a channel other than the desired channel that is output from the switcher. A receiver comprising: a determiner for determining a channel.