JPS593711B2 - signal detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a signal detection device suitable for a system that utilizes the frequency swept wave response characteristics of a resonant circuit.

In general, a transmitting device sends a frequency swept wave signal to a responding device including a plurality of resonant circuits each having a different resonance frequency, and a receiving device processes the frequency swept wave response from the responding device. As a system for identifying information specific to an object, an identification system as shown in FIG. 1 is known.

That is, the frequency sweep wave signal from the sweep signal generator 1 is amplified by the power amplifier 2, and is emitted as an interrogation radio wave from the transmitting/receiving antenna 3 via the hybrid circuit 12 toward the response device.

The response device 4 is attached to, for example, a part of an object traveling at high speed, and receives the interrogation radio wave with a response antenna 5.

A plurality of resonant circuits 7 are connected to the antenna 5 in parallel via a capacitor 6.

It has 7□...7□.

Each resonant circuit 71, 72, .

Therefore, when the frequency of the interrogation signal reaches the resonant frequency, if the resonant element is a series resonant circuit, the impedance of the resonant circuit decreases and a large current flows through the response antenna 5. 72...
Radio waves are reflected in response to In.

The reflected radio wave is guided to the transmitting/receiving antenna 3, passes through the hybrid circuit 12, and the P-wave unit 8 extracts only the signal in the required band to obtain a signal as shown in FIG. 2a.

In addition, in Fig. 2a, there are two frequency response signals,
Next, the case where there are four noise signals is shown.

The hybrid circuit 12 has the directionality of guiding the interrogation radio wave from the power amplifier 2 to the transmitting/receiving antenna 3 and guiding the reflected radio wave from the response device 4 to the R wave generator 8 .

Also, as the r-wave device 8, a bandpass p-wave device is usually used, but
A low-pass r-wave device may also be used.

The radio wave reflection from the above response antenna 5 to the transmitting/receiving antenna 3 can be regarded as the frequency swept wave response of the response device 40 when looking at the response device raw from the transmitting/receiving antenna 3. By using this as a reference phase and comparing the signals of the transmitting and receiving antenna 3 with a phase detector 10, the phase change can be detected.

The phase detector 10 is preferably a product-type detector proportional to the amplitude and phase difference between the input signal and the reference signal, such as a ring modulator, from the viewpoint of detection sensitivity, but a phase detector such as a ratio detector is preferable. can also be used.

The output signal of the phase detector 10 (see FIG. 2) is converted into a binary signal by a level detector 11 such as a Schmitt circuit.

By processing this binary signal (see FIG. 2C), an object having a response device signal is identified.

By the way, when high reliability is required in the above-mentioned signal detection device, a standby dual system with a relatively simple configuration has been commonly used in consideration of redundancy.

That is, in FIG. 3, two sets of systems each consisting of a sweep signal generator 1, a power amplifier 2, an F-wave unit 8, a phase shifter 9, a phase detector 10, and a level detector 11 are provided, and the power amplifier 2 of each set is The output of the hybrid circuit 1 is selected by the system changeover switch 31.
2 shows a conventional standby dual-system signal detection device configured to input the received output of the hybrid circuit 12 to the R wave generator 8 of each set in common.

Note that the same parts in FIG. 3 as in FIG. 1 are designated by the same reference numerals, and the explanation thereof will be omitted.

In the above configuration, due to the nature of the standby dual system, the f-wave unit 8, phase shifter 9, phase detector 10, level detector 112, and subsequent signal processing system (not shown) are ,
Only one set, ie, one system, performs a processing operation, and the other system does not perform any processing operation.

However, this is a major drawback especially when high reliability is required.

In other words, the signal detection device described above is used, for example, to detect an object moving at high speed, but considering that the amount of information obtained in such cases is generally very small, the reception signal processing system is Because it is a heavy-duty system, if the circuit in use malfunctions for some reason, a serious erroneous detection occurs2.

Furthermore, the reference signal input to the transfer device 90 is supplied from the sweep signal generator 1 of one system to the transfer device 9 in the same hole, and from the sweep signal generator 1 of the other system to the phase shifter 9 in the same system. Because of this, it had the following drawbacks:

For example, when the sweep signal generator 1 and power amplifier 2 of one system are operating, the frequency sweep response from the response device raw is as follows.
It depends on the characteristics of the sweep signal generator 1 in the operating system.

On the other hand, the reference signal input to the phase detector 100 is supplied from the sweep signal generator 1 in each system via the phase shifter 9.

For this reason, the phase detector 10 in the non-operating system is such that the frequency sweep response input from the response device depends on the sweep signal generator 1 in the operating system, and the reference signal input depends on the sweep signal generator 1 in the non-operating system. , a balance between the 1Ω sweep characteristics of the sweep signal generators of both systems is required.

If such balance is required, the configuration of the sweep signal generator 1 becomes complicated and expensive.

The present invention has been made in view of the above circumstances, and improves reliability by providing redundancy to each of the transmitting and receiving systems, and also sweeps the 7J pull signal supplied to the transmitting and receiving antennas and the reference input of the phase detector. The present invention provides a signal detection device that does not require balancing the characteristics of a plurality of sweep signal generators by supplying signals from the same generator, and that allows the sweep signal generator to have a simple configuration.

An embodiment of the present invention will be described in detail below with reference to the drawings.

The signal detection device shown in FIG. 4 differs from the conventional signal detection device described above with reference to FIG. The difference is that the switching control of the system switching device 42 is performed based on the monitoring output of the power amplifier 41, and the output of the normally operating power amplifier 2 is guided to the hybrid circuit 12.

The reception system is a standby triple system guided by the reception output signal of the hybrid circuit 12, and outputs from each system are sent to a majority logic circuit (not shown).

), and uses majority logic to increase information reliability, which is different from the one in Figure 3.

In addition, the reference signal input to the phase shifter 90 of each reception system is the output of the normally operating sweep signal generator 1 of each transmission system to the system switch 4.
2 differs from the one in FIG. 3 in that it is selected and derived.

Since the other parts are the same, the same reference numerals as in FIG. 3 are given in FIG. 4, and the explanation thereof will be omitted.

In the signal detection device having the above configuration, by monitoring the output level of the power amplifier 2 with the level monitor 41, if the output level of the power amplifier 2 of one system is normal, the output of this power amplifier 2 is selected. If the output level of the power amplifier 2 of one system decreases and becomes abnormal, the system is switched so that the output of the power amplifier 2 of the other system is selected and supplied to the hybrid circuit 12. The vessel 42 works.

At the same time, the system switch 42 selects the output of the sweep signal generator 1 of the same system as the power amplifier 2 of the system whose output is selected as described above, and supplies it to the phase shifter 9 of each receiving system. Work.

That is, according to the above signal detection device, in order to supply a sweep signal to the transmitting/receiving antenna 3 via the power amplifier 2, the sweep signal is sent as a reference signal to the phase detector 10 to which the response signal received by the transmitting/receiving antenna 3 is guided. A common sweep signal generator 1 is used to supply the signals.

Therefore, although reliability is improved by the transmission system having a standby dual system configuration and the receiving system having a standby triple system configuration, it is necessary to balance the characteristics of the sweep signal generator 1 of each transmission system, which was required in the past. There is no need to consider such matters.

For this reason, the sweep generator 1 has the advantage of being simple in configuration and can be realized at low cost.

In the above embodiment, a standby triple system configuration was used as the reception system, but a sweep signal that supplies a sweep signal to each phase shifter 9 of the standby dual system configuration reception system as shown in FIG. Generator 1
Substantially the same effect as in the above embodiment can be obtained even if switching control is performed based on the level monitoring results so that the output of one system or the other system is selected as the output of the system.

As described above, the present invention improves reliability by providing redundancy to each of the transmitting and receiving systems, and also generates a sweep signal to be supplied to the transmitting and receiving antennas and a sweep signal for the reference input of the phase detector from the same generator. By supplying
No need to balance the characteristics of multiple sweep signal generators,
It is possible to provide a signal detection device in which the configuration of the sweep signal generator is simple.

[Brief explanation of drawings]

FIG. 1 is a configuration explanatory diagram showing a conventional signal detection device, and FIGS. 2 a to C are waveform diagrams shown to explain the operation of FIG. 1.
FIG. 3 is a configuration explanatory diagram showing a conventional standby dual system signal detection device, and FIG. 4 is a configuration explanatory diagram showing an embodiment of the signal detection device according to the present invention. 1...Sweep signal generator, 2...Power amplifier, 3...Transmitting/receiving antenna, 4...
Response device, 10... Phase detector, 41...
...Level monitor, 42...System switching a

Claims (1)

[Claims] 1. Transmitting means having a redundant system for transmitting a frequency sweep signal to the resonant circuit, monitoring means for monitoring the transmission output level of the transmitting means, and detection means having a redundant system for detecting the frequency sweep response signal of the resonant circuit. and system switching means that is controlled by the monitoring result of the monitoring means and selects an output of a system that is transmitting a sweep wave signal to the resonant circuit among the transmitting means and supplies it to the detection means as a reference signal. A signal detection device characterized by: