JPS6248931B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pulse repetition period identification method for detecting the period of each pulse train from a pulse train in which a plurality of pulse trains with different periods coexist.

2. Description of the Related Art In an aircraft or the like that receives a radar signal and detects its transmission source, the radar signal being received contains a mixture of high-frequency pulses having various repetition periods, and it may be difficult to identify each oscillation source.
Therefore, it becomes necessary to identify a particular pulse train from a received pulse signal.

The present invention has been made in view of the above-mentioned points, and is a novel pulse repetition period identification system that separates and detects a pulse train having a constant period from a mixed pulse train of a plurality of pulse trains each having a different repetition period input during a limited period. It provides a method.

Preferred embodiments of the present invention will be described below with reference to the drawings.

First, the principle of the present invention will be described. Consider a mixed pulse train P of three pulse trains each having different repetition periods τ _A , τ _B , and τ _C that are input during a limited period T as shown in FIG. Here, the input times of each pulse of the mixed pulse train P are T ₀ , T ₁ , T ₂ ,...
..., T _i-1 , ... T _o , and the time intervals to each pulse with T ₀ as the reference point are S ₁ , S ₂ , ..., S
_i-1 , S _i , ..., S _o and τ _A < τ _B < τ _C
Suppose that The maximum _time interval τ _n between two adjacent pulses of such a mixed pulse train P is τ _n =T _{i +1} − _{T i} in the case of FIG. At least one of the pulses belongs to the pulse train with the minimum repetition period. Therefore, with this τ _n as a divisor, either T _i or T _i+1 , for example T _i, is the reference time, and from T _i to T _{i +1} , T _{i +2} , . . . , T Sequentially divide the period up to _o . At this time, if the frequency obtained by dividing and obtaining an integer value is equal to the value of T _n /τ _n , then this time τ _n matches the period of the pulse train with the shortest repetition period included in the mixed pulse train P. In the mixed pulse train P of FIG. 1, τ _n =τ _A. Here, T _n is the time from the reference time T _i to T _o .
If an integer value cannot be obtained for T _n /τ _n at this time, or if the frequency at which the integer value can be obtained is different from the value of T _n /τ _n , a pulse train whose repetition period is τ _n is added to the mixed pulse train P. does not exist. Then, using T _{i +2} - _{T i} as a divisor, we sequentially divide the period up to each pulse of the pulse train P with T _i as the reference time again, and the frequency at which an integer value is obtained is T _n /
If it is equal to the value of (T _i+2 −T _i ), then this T _i+2 −T _i
The repetition period mixed in the mixed pulse train P is T _{i +2}
- corresponds to the period of the pulse train of T _i . If the frequency of integer values obtained in the above method is T _n /(T _i
+2 −T _i ), this means that a pulse train whose repetition period is T _i+2 −T _i does not exist in the mixed pulse train P. In such a case, the time from time T i-1 to each pulse of the pulse train P is sequentially divided using T _i+1 −T i _{- 1} as a divisor.
At this time, the number of integer values obtained is T _n ′/(T _i+1
-T _i-1 ), T _i+1 -T _i-1 means that the repetition period mixed in the mixed pulse train P is T _i+1 -T _i-1
corresponds to the period of the pulse train. Here T _n ′=T _o
-T _i-1 . The repetition period of any one of the three pulse trains included in the mixed pulse train P can be detected by any of the above methods. By removing the pulses having the repetition period detected in this way from the mixed pulse train P and using the remaining pulse train as the mixed pulse train P' and repeating the above method again, the mixed pulse train
The repetition period of either one of the two pulse trains mixed in P′ can be detected, and the pulse with this detected period is removed from the mixed pulse train P′, and the remaining pulse train is set as P″ and the same repetition period is detected. By performing this operation, it is possible to detect the repetition period of the last remaining pulse train.As can be seen from Figure 1, the mixed pulse train when τ _A < τ _B < τ _C and the difference is large. The maximum value τ _n of the interval between two adjacent pulses at P coincides with the period of the pulse train whose repetition period is τ _A , and furthermore, τ
The maximum value τ _n ' of the interval between two adjacent pulses in the remaining mixed pulse train P' after removing the pulse having a repetition period of _A from the mixed pulse train P' matches the period of the pulse train having a repetition period of τ _B. In this way, the maximum value of the interval between two adjacent pulses in a mixed pulse train often matches the period of the pulse train with the minimum repetition period included in the mixed pulse train. Therefore, when detecting the period of each pulse train in the mixed pulse train, it is an efficient method to first select the maximum pulse interval in the mixed pulse train as the divisor.

FIG. 2 is a block diagram showing an embodiment of the circuit used in the pulse repetition period identification method according to the present invention, in which the mixed pulse train input to the pulse train input terminal 1 is stored via the pulse interval integration circuit 2. The memory circuit 3 is added to the circuit 3 and stores the time interval from the first pulse to each pulse of the mixed pulse train P obtained by the pulse interval integration circuit 2. The maximum pulse interval detection circuit 4 detects the maximum pulse interval from the pulse interval integrated data stored in the storage circuit 3,
It is sent to the divisor selection circuit 5. The divisor selection circuit 5 sends the inputted maximum pulse interval as the selected divisor to the division circuit 6, and also determines the pulse interval corresponding to the selected divisor according to the judgment result from the divisor judgment circuit 8, which will be described later. It is sent to the output terminal 10 as a pulse repetition period identification output, or alternatively, a pulse interval that should become a new predetermined divisor is selected and sent to the division circuit 6. Division circuit 6
reads from the memory circuit 3 the time from either one of the two pulses having the time interval that should be the divisor selected by the divisor selection circuit 5 to each pulse of the mixed pulse train P, and sequentially calculates this time using the divisor selected. The division is carried out and the result is sent to the regular divisor detection circuit 7. The regular divisor detection circuit 7 detects the pulse of the divided time from the result of the division, and sends it to the regular divisor determination circuit 8 and the detection pulse removal circuit 9.
The divisor determination circuit 8 determines whether the divisor reaches a predetermined frequency, and sends the result to the divisor selection circuit 5 and the detection pulse removal circuit 9. If the divisor frequency does not reach a predetermined number, the divisor selection circuit 5 selects a new pulse interval that should be a predetermined divisor based on the determination result from the divisor determination circuit 8, and sends it to the division circuit 6. The same operation is repeated until the frequency to be divided reaches the predetermined frequency. When the division result reaches a predetermined frequency, the divisor selection circuit 5 sends the pulse interval forming the divisor selected at that time to the output terminal 10 as a pulse repetition period identification output, and on the other hand, the detection pulse removal circuit 9 outputs the pulse interval forming the divisor selected at that time. Pulses for which an integer value is obtained by dividing by the selected divisor are removed from the mixed pulse train P stored in the storage circuit 3.

Next, the operation of the embodiment shown in FIG. 2 will be explained with reference to FIG. The memory circuit 3 stores the time S ₁ to each pulse with the first pulse of the mixed pulse train P obtained by the pulse interval integration circuit 2 as a reference point,
S ₂ , ..., S _o are stored. The maximum pulse interval detection circuit 4 detects the maximum pulse interval τ _n from the pulse interval integrated data stored in the storage circuit 3 and sends it to the divisor selection circuit 5 . The divisor selection circuit 5 sends τ _n as the selected divisor to the division circuit 6, and the division circuit 6 calculates the pulses up to each pulse of the mixed pulse train P using one of the two pulses separated by τ _n as the reference time. Time S _i+1 −S _i , S _i+2 −S _i , ..., S _o
-S _i is sequentially detected from the storage circuit 3, sequentially divided by τ _n , and the result is sent to the regular divisor detection circuit 7. The regular divisor detection circuit 7 detects pulses _PA1 , _{PA2 ,} . The divisor power judgment circuit 8 is P _A1 ,
_It is determined whether _{the number of} P _{A2 , .} Send to circuit 9. In the case of the _mixed pulse train P _shown in FIG.
..., if the number of P _A7 is equal to the value of T _n /τ _n , a determination result that they are equal is sent, and the divisor selection circuit 5 outputs τ _n to the output terminal 10 as a pulse period identification output. On the other hand, the detection pulse removal circuit 9 removes the mixed pulse train P from the mixed pulse train P stored in the storage circuit 3.
Remove pulses _A1 , P _A2 , ..., P _A7 .
The output τ _n at this time matches the repetition period of the pulse train whose period is τ _A mixed in the mixed pulse train. At this point, the memory circuit 3 stores P _A1 , P _A2 , ..., P _A7 of the mixed pulse train P.
The pulse train with the removed pulse train, that is, the repetition period is τ
The period up to each pulse of pulse train P' in which pulse trains _B and τ _C are mixed is stored. Then, the maximum pulse interval detection circuit 4 determines the maximum pulse interval τ.
Find _n ′ and perform similar operations as above to find τ
_n ' is output from the divisor selection circuit 5, and pulses P _B1 , P _B2 , and P _B3 are deleted from the mixed pulse train P'. The output τ _n ′ at this time matches the period of the pulse train whose repetition period is τ _B which is mixed in the mixed pulse train P′. Also, at this point, the memory circuit 3 stores P _B1 and P _B of the mixed pulse train P'.
₂ , the pulse train with P _B3 deleted, that is, the period up to each pulse of the pulse train P'' with a repetition period τ _C is stored.Therefore, the pulse interval detection circuit 4
The maximum pulse interval τ _n ″ is detected by this, and the same operation as described above is repeated again to send out τ _n ″ that matches the period of the pulse train with the repetition period τ _C.

In this way, the period of each pulse train whose repetition period is τ _A , τ _B , and τ _C constituting the pulse train is identified from the input mixed pulse train.

In the above embodiment, the input mixed pulse train is composed of three pulse trains with greatly different repetition periods, but the present invention is not limited to this, and each mixed pulse train can have an arbitrary repetition period. Even if the mixed pulse train is composed of two or more pulse trains, the present invention can be applied to identify the repetition period of each pulse train forming the mixed pulse train.

As is clear from the above description, the pulse repetition period identification method according to the present invention easily determines the repetition period of each pulse train from a mixed pulse train in which a plurality of pulse trains each having a different repetition period are input during a limited period. Since it can be identified as
It is extremely useful for use in pulse repetition frequency identification devices, etc.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a mixed pulse train, and FIG. 2 is a block diagram showing an embodiment of the present invention. 1...Input terminal, 2...Pulse interval integration circuit, 3...
Memory circuit, 4... Maximum pulse interval detection circuit, 5... Divisor selection circuit, 6... Division circuit, 7... Regular division power detection circuit, 8... Regular division power determination circuit, 9... Detected pulse removal circuit, 10... Output terminal.

Claims (1)

[Scope of Claims] 1. The pulse interval is configured by setting the time interval between two pulses belonging to a mixed pulse train, which is a mixture of multiple pulse trains each having a different repetition period and input during a limited period as a divisor, as a divisor. a first operation of sequentially dividing the time from either one of the pulses to each individual pulse in the mixed pulse train;
a second operation of repeating the same operation by changing the pulse interval serving as the divisor until the frequency of the division result obtained by the integer value reaches a predetermined number; A pulse repetition period identification method characterized in that, when the pulse interval matches a predetermined number, the pulse interval used as the divisor is identified as the repetition period of one system of pulse trains in the mixed pulse train. 2. Pulse repetition period identification according to claim 1, characterized in that the pulse interval used as a divisor in the first operation is selected to be the largest among the time intervals of two adjacent pulses belonging to the mixed pulse train. method.