JPH0349314A - Probability control filter - Google Patents

Abstract

PURPOSE:To eliminate a noise component from a pulse train signal singly by eliminating n-set of pulses when a pulse number N of an inputted 1st pulse train is larger than a predetermined pulse number (n), outputting a pulse train whose pulse number is '0' when number N is equal to or smaller than the number (n) and adding predetermined m-set of pulses. CONSTITUTION:A pulse train comprising N-set of pulses is inputted to a pulse train input terminal 1a, a single pulse is inputted to a pulse train input timing signal input terminal 1b just before the pulse train is inputted to the pulse train input terminal 1a, the upper limit of a steady-state noise component DELTAN included in the input pulse train is 16 and the succeeding system is responsive even with one pulse output, then when tue number N of the input pulses is larger than 16, 16 pulses are subtracted from the N-set of pulses and one pulse is added to be N-15 pulses in total are outputted from a pulse train output terminal 4 and when the input pulse number N is 16 or less than 16, only one single pulse is outputted from the pulse train output terminal 4.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a stochastic control filter, and in particular to a method for removing noise component pulses contained in a pulse train signal in which the number of pulses represents a physical quantity, such as a phase difference signal of a digital phase synchronization circuit. This invention relates to a stochastic control filter, a so-called random walk filter.

[Conventional technology]

The digital phase-locked circuit has a built-in stochastic control filter, which ultimately functions to remove noise components from the pulse train signal (for example, Journal of the Institute of Electronics and Communication Engineers, 56-A (12). ) (Sho 48-1
2) P, 751-758>.

[Problem to be solved by the invention]

However, the above-mentioned conventional stochastic control filter operates only when incorporated into a phase locked circuit, and cannot be used alone to remove noise components from a pulse train signal.

An object of the present invention is to provide a new stochastic control filter that has the function of independently removing m fJ acid components from a pulse train signal.

[Means to solve the problem]

The probability control filter of the present invention removes n pulses from the first pulse train when the number N of pulses of the input first pulse train is larger than a predetermined number n of pulses, and a first means for outputting a pulse train with a pulse number of 0 as the second pulse train when the number of pulses is equal to or smaller than the number of pulses; -n+m
or a second means for outputting a third pulse train of the number m of pulses.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram of one embodiment of the present invention.

In FIG. 1, 1a is a pulse train input terminal, 1b is an input terminal for a signal that gives the timing to start inputting a pulse train to the pulse train input terminal 1a, and 2 is a presettable up/down counter 2a (for example, NEC's μPD4029
B), monostable multivibrator 2b (e.g. US GE
CD4098B), a circuit that removes the first 16 pulses from a pulse train consisting of N pulses input to the pulse train input terminal 1a, including AND gates 2C and 2d;
3 is an OR gate 3a, a monostable multivibrator 3b (
For example, the circuit includes a CD4098B (manufactured by GE, USA) and adds one pulse to the pulse train output of the AND gate 2d. 4 is a pulse train output terminal.

Next, the operation of the embodiment shown in FIG. 1 will be explained.

FIG. 2 is an operation time chart of the embodiment shown in FIG.

It is assumed that a pulse train consisting of N IIN pulses is input to the pulse train input terminal 1a, and a single pulse is input to the pulse train input timing signal input terminal 1b immediately before the pulse train is input to the pulse train input terminal 1a. However, the input pulse train is a numerical input quantized by the number of pulses,
The number of pulses indicates a certain physical quantity, and this number of pulses includes a signal component and a noise component. That is, when the number of pulses corresponding to the true physical quantity is Ns, the actual input pulse train consists of N=Ns+ΔN pulses (Ns: signal component, ΔN: noise component).

In the embodiment shown in FIG. 1, it is assumed that the upper limit of the stationary noise component ΔN included in the input pulse train is 16. Also,
It is assumed that the system following this example also responds with a single pulse output.

When a single pulse signal of pulse train input timing is input to the pulse train input timing signal input terminal 1b, the rising edge of this signal causes the monostable multivibrator 2 to
A sufficiently short single pulse is generated from b, and the JAM input of the up/down counter 2a is set to 0. At this time, the co output of the up/down counter 2a becomes H (High), the AND gate 2c opens, and the pulse train at the pulse train input terminal 1a is input to the CLOCK input of the up/down counter 2a.

When the count value of the up/down counter 2a reaches 15, the C0 output of the up/down counter 2a becomes L (L
ow), and the AND gate 2c is closed. During this time, one pulse is input while the JAM input of the up-down counter 2a is set to 0, so a total of 16 pulses are input to the CLOCK input of the up-down counter 2a.

The ADN gate 2d operates in conjunction with the AND gate 2c, and passes the 17th and subsequent pulses of the pulse train input.

After setting the JAM input of the up/down counter 2a to 0, the monostable multivibrator 3b generates one single pulse, and both this pulse and the pulse that has passed through the AND gate 2d are output to the pulse train output terminal 4 by the OR gate 3a. Output. Therefore, if the number N of input pulses is more than 16, 16 pulses are removed from N and 1 pulse is added to the pulse train output terminal 4, so N-16 ÷
1=N-15 pulses are output. Further, if the number N of input pulses is 16 or less than 16, only one pulse is output.

A similar circuit is constructed by selecting the number n of pulses to be removed from the input pulse train and the number m of pulses to be added depending on the properties of the input pulse train.

〔Effect of the invention〕

As explained above, the stochastic control filter of the present invention outputs N-n+m or m pulse trains for N input pulse trains, and therefore has the following effects.

It is assumed that the input pulse train N consists of a signal component Ns and a noise component ΔN. That is, N=N, +ΔN Also, assume that the input pulse train has polarity and is transmitted to the subsequent system together with the pulse train (the number of pulses represents a physical quantity) (for example, in a phase locked circuit, the input pulse train is a phase difference signal). (e.g., when there are two polarities: leading phase and lagging phase).

Now, when the signal component N is smaller than the noise component ΔN,
The number n of removal pulses of the stochastic control filter of the present invention is ΔN
If you choose a value larger than the steady value of , you can get N, +ΔNun. At this time, the probability of occurrence of the polarity Ns+ΔN changes depending on the value of N5, and the probability control filter outputs m pulses. Therefore, the noise component ΔN is not transmitted to the subsequent system, and the signal component Ns is transmitted according to the probability of occurrence of polarity.

Next, when the signal component N5 is sufficiently larger than the noise component ΔN, N=N-n+m. Therefore, the signal component NS is transmitted to the subsequent system.

That is, there is a filter effect of removing noise components from the input pulse train.

However, when there is not much difference between the values of the signal component N5 and the noise component ΔN, the linearity between the input and output of the stochastic control filter of the present invention is no longer linear.

[Brief explanation of drawings]

FIG. 1 is a block diagram of one embodiment of the present invention, and FIG. 2 is a block diagram of an embodiment of the present invention.
3 is an operation time chart of the embodiment shown in the figure. 1a... Pulse train input terminal, 1b... Pulse train input timing signal input terminal, 2... Pulse removal circuit, 2a...
...up-down counter, 2b, 3b...monostable multivibrator, 2c, 2d...AND gate, 3
...Pulse addition circuit, 3a...OR gate, 4...
・Pulse train output terminal.

Claims (1)

[Claims] When the number N of pulses of the input first pulse train is larger than the predetermined number n of pulses, n from the first pulse train
a first means for outputting a second pulse train with a number of pulses N-n by removing the pulses, and outputting a pulse train with a number of pulses of 0 as the second pulse train when the number of pulses is equal to or smaller than the second pulse train; and second means for adding a predetermined m number of pulses to the output to output a third pulse train having the number of pulses N-n+m or the number of pulses m.