JPH0226133A - Receiving wave interference detector - Google Patents

Abstract

PURPOSE:To prevent the influence of an interfering wave by providing a timer circuit to output an identification signal as the interfering wave only when the time of the interfering wave to be an initial setting value is detected in a constant time and automatic switching a channel for control to a channel for frequency alternation. CONSTITUTION:When a reception input 1 is received, A and B timer circuits 5 and 6 are simultaneously reset. When the noise is detected by a noise squelch circuit built-in a receiving member, not to be shown in a figure, the circuits 5 and 6 are simultaneously started and only the circuit 5 continues counting. On the other hand, the circuit 6 executes integrating counting only when the noise is detected. Next, since a time is set for the circuit 5, if the integrating value of the circuit 6 is larger than the prescribed integrating value of the circuit 5 when the time comes up, the interfering wave is identified. The control channel is automatically switched by a frequency alternation trigger circuit 7 and a frequency alternation control output is inputted to the receiver of a rear step.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention, for example, identifies and detects interference waves and desired waves received by a digital communication control channel in data transmission through a digital transmission network, etc. This invention relates to a received wave interference detection device.

[Conventional technology]

FIG. 15 is a basic block diagram showing an overview of a conventional communication system. In FIG. 9, 11 is a control station;
2, a transmitting/receiving device 13 and a storage device 14. Further, 15 is the transmitting/receiving device r! 1. An antenna system connected to 13, for example, performs bidirectional communication between the mobile station 16 and the command station 17, the control channel 18, and the communication channel 19. 20 is an interfering wave, and 21 is an interfering wave mobile station. .

Next, the operation will be explained. First, control station 11 and command station 1
7, a digital communication control channel 18 and a communication channel 19 are used for communication.

Further, communication is carried out between the mobile station 16 and the control station 11 through a communication channel 19. However, when the power of the interference wave 20 output from the interference wave mobile station 21 approaches the communication output of the suppression channel 18 and the communication channel 19, the interference wave 20
Communication may become impossible due to the influence of Conventionally, there has been no effective interference detection means for the control channel receiver that receives the control channel 18 signal, that is, the interference waves 20 to the control station 11, and no special measures against interference have been taken. is the actual situation.

[Problem to be solved by the invention]

The conventional received wave interference detection device is configured as described above, so that the control channel receiver can detect other radio noise sources,
Alternatively, if interference noise is received by an illegally modified radio, the noise will be emphasized and the digital transmission system may become temporarily unusable.

This invention was made in order to solve the above-mentioned problems, and even when a control channel receives an interference wave, it is possible to distinguish between the interference wave and the desired wave and continue communication. The purpose is to obtain a detection device.

[Means to solve the problem]

The received wave interference detection device according to the present invention uses the carrier of the desired wave inputted to the control channel receiver of digital communication and the duration of the interference wave as reception inputs, and receives A for a predetermined period of time.
247 circuit and a B timer circuit, and when the time of the A247 circuit is up, the reception time of only the interference wave output is measured, and the interference wave initial setting value is inputted and compared with the initial setting value of the interference wave in the B timer circuit, The identification result is input to a frequency substitution trigger circuit to output a switching signal as a frequency substitution control output. That is, as a means for distinguishing between desired waves and interference waves, attention is paid to the fact that desired waves are received at regular intervals, whereas interference waves are received continuously for a certain period of time.

[Effect]

The received wave interference detection device according to the present invention is a means for identifying interference waves, and outputs an identification result as an interference wave only when a time of interference waves exceeding an initial setting value is detected within a certain period of time.B
A timer circuit is provided, and by changing the ratio of the initial setting value, it is possible to automatically switch the control channel to the frequency substitution channel side so that frequently received interference waves can be detected.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. 1st
FIG. 2 is a block diagram of a received wave interference detection apparatus showing an embodiment of the present invention, and FIG. 2 is a flowchart showing the operation of FIG. 1. In FIG. 1, 1 is the reception input of the receiver, 2 is the frequency proxy control output that provides only the desired signal to the receiver (not shown), 3 is the carrier detection circuit, and 4 is the activation of the A timer circuit 5 in the subsequent stage. Trigger circuit, 5 is A247 circuit,
6 is a B timer circuit that measures the carrier signal time via the carrier detection circuit 3, 7 is a frequency proxy trigger circuit, 8 is a reset signal, and 9 is an initial setting value for presetting the time of the B timer circuit 6.

Next, the operation shown in FIG. 1 will be explained with reference to the operation flowchart shown in FIG. First, the A timer circuit 5 and the B timer circuit 6 are in an initial reset state (step 5T).
I) A noise squelch circuit built into the receiver (not shown) or an electric field squelch circuit (squelch circuit; there is a phenomenon in which very large noise appears in the output of a frequency modulation receiver when the received carrier wave disappears). Therefore, a squelch circuit that operates to prevent the receiver from being disturbed by the noise is built in so that the noise does not appear even if the carrier wave disappears.) When noise or limiter current is detected, the A, The B timer circuit 5.6 starts counting for a certain period of time.

Therefore, when receiving human power 1, A and B timer circuits 5.6
are reset at the same time. When noise or limiter current is detected, A and B timer circuits 5 and 6 are started simultaneously, and only A timer circuit 5 continues counting, while B timer circuit 6 detects noise or limiter current. Only the time spent is counted (Stella 7ST)
3) Next, since the A timer circuit 5 is resetting the time, when the reset time is reached (step 5T4)
, the integrated value of the B timer circuit 6 is compared with the integrated value of the B timer circuit 6, and if the integrated value of the B timer circuit 6 is larger than the predetermined value of the integrated value of the A timer circuit 5, that is, the integrated value of noise is greater than a certain value, it is considered to be an interference wave. Then, the control channel is automatically switched by the frequency proxy trigger circuit 7 (Steps 5T5A and 5T6), and the frequency proxy control output is input to the subsequent receiver (Step 5
T6).

In the above embodiment, a received wave interference detection device was described that uses the B timer circuit 6 to start at the same time as the A timer circuit 5, and performs cumulative counting for a certain period of time when noise or limiter current is detected. shows another embodiment, in which a counter circuit 10 for counting the number of interference waves is provided in place of the B timer circuit 6. In this case, as shown in the flowchart of FIG.
Up to T4, the same operation as in FIG. 1 is continued, and instead of the time accumulation in step 5T5A by the B timer circuit, interference wave detection is performed by the counter circuit 10, which is initialized to a predetermined value. Only when the interference waves are counted and overflows beyond the initial setting value 9 (Step 5T5B>), a radio interference detection signal is output (Step 5
T6).

〔Effect of the invention〕

As described above, according to the present invention, when controlling a control channel through digital communication, even when interference waves and desired waves are input to a receiver, only the interference waves can be measured for 9 hours or counted using the B timer circuit or counter. Since a circuit has been installed to enable comparison and identification, the digital communication system will not go down due to the influence of interference waves, and the system can be continuously operated because it can automatically switch to the alternate frequency channel. There are effects that can be implemented.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a received wave interference detection device according to an embodiment of the present invention, FIG. 2 is a flowchart showing the operation of FIG. 1, and FIG. 3 is a block diagram of a received wave interference detection device according to another embodiment. FIG. 4 is a flowchart showing the operation of FIG. 3, and FIG. 5 is a basic block diagram of a conventional communication system. In the figure, 1 is the reception input, 2 is the frequency substitution control output,
3 is a carrier detection circuit, 4 is a trigger circuit, 5 is an A timer circuit, 6 is a B timer circuit, 7 is a frequency substitution trigger circuit,
8 is a reset signal, 9 is an initial setting value, and 10 is a counter circuit. Note that the same reference numerals in the figures indicate the same or equivalent parts. Figure 4

Claims (1)

[Claims] Digital communication is performed by transmitting control signals for controlling the control channel and speech signals for the plurality of speech channels using a relay device composed of one control channel and a plurality of speech channels. In this case, a carrier detection circuit that receives the control channel signal and noise and takes it in as a reception input, an A timer circuit that is triggered by the output signal of the carrier detection circuit and has been reset in advance, and an A timer circuit that has input the initial setting value. After a predetermined time has elapsed after the B timer circuit and the A timer circuit operate, the B timer circuit compares the reception time of the interference wave counted by the B timer circuit with an initial setting value to identify the interference wave, and determine the frequency. A received wave interference detection device comprising a frequency proxy trigger circuit that outputs a proxy control output.