JPS58134560A - Asynchronous signal detection system - Google Patents

Abstract

PURPOSE:To hold a readout error within a specific value, by varying an input signal readout period according to signal order at every sampling period, and reading an input signal. CONSTITUTION:An FSK-modulated signal is demodulated by a demodulation part 28 into a digital signal 26, which is inputted to a detection part 29. Every time ''1'' of the input signal is received, the signal value read part 30 of the detection part 29 adds 1 to the counted value of a signal receiving circuit counting part 31 and when the sum reaches some value, the read part 30 reads the input signal to generate an output and also clears the counting part 31 to ''0''. The output of the read part 30 is ANDed with the output of the counting part 31 to generate a signal value output of the 1st order. Then, said operation is repeated to obtain signal values of the 2nd and succeeding order at corresponding output terminals of a signal order detection and display part 32. Those signal values are read as a readout value 27 to detect an original signal sequence and signal values.

Description

[Detailed description of the invention] (j) Technical field of the invention: Fukaisha, asynchronous binary im-number data, for example, FSX
(Frmqma Dairy 5haft Keying)
This invention relates to an asynchronous signal detection method for detecting an original signal from a discrete signal obtained by sampling a modified asynchronous signal at regular time intervals.

(B) Prior art and problems Conventionally, an original remark sequence from temporally consecutive asynchronous binary numbers,
A decoder for detecting signal values reads the input signal values at regular time intervals, detects the signal rank, and the signal value. That is, as shown in FIG. 1, if the input signal 1 is read at constant time intervals starting from the temporal center position 7 of the start signal 2, then k
In this case, the signal value at the temporal center position 10 of the signal 50 of the fifth Jli rank is detected from the signal value at the temporal center position 8 of the signal 30 of the first rank. In this method, since the input signal is not discrete but continuous, the error can be set within a desired range by setting the sampling rate sufficiently high. This error is generally considered to be within 5 seconds (reception marsh 45- or more), for example, 30
07/# In the case of an asynchronous wandering number, it is necessary to suppress the difference by 167μIK. However, for discrete input signals, the sampling period cannot be set freely; for example, 300 b
In the 64 K b/a @ code, which uses BKHz sampling (sampling period: 125 μJ) and 8-bit encoding for the /s non-synchronized signal, the reading error per signal is 86 μm earlier or 42 μm slower. Even if the temporal center position 7 of the start signal 2 shown in Fig. 1 is detected without any difference, an error of 664 μs at the maximum and 556 μm at the minimum will occur when reading 8 signals (8 Acts). It turns out. Therefore, in order to suppress the error within the receiving marsh, it is necessary to convert the L digital signal to an analog signal and, as mentioned above, to make the sampling clock sufficiently small, which requires extra equipment such as a digital/analog converter. , it was uneconomical.

<c> Purpose of the Invention “The present invention attempts to solve these drawbacks, and its purpose is to change the signal sampling frequency in units of sampling periods in accordance with the signal priority and input it. (D) Embodiment of the Invention FIG. 2 shows the operation of an embodiment of the present invention. is an input signal (discrete 2-chain system number) 2 is a start signal, !IJ1J1 rank signal, 4 is a 1jpJ2 rank signal, 5 is a calculation rank signal, 6 is an end signal, 7 is a start signal , aFi is the temporal center position of the first order signal, 9 is the time center position of the second order signal, 10 is the time center position of the first order signal, and 11 is the time center position of the end signal. The temporal center position, 12 is the detection timing of the head of the start signal, 13 is the reading timing of the start signal value, and 14 is the first order signal fl!
L line * time, 15iith b-th signal value reading time, 17 is the end signal value reading time, 18 is the detection error at the beginning of the start signal, 19 is the start signal value reading difference, 20 is 11th wish rank Hakugo value indulgence sim
, p, , 21 is the color value difference of the second rank, 22d#
41 is the reading error that exceeds the difference limit value, 23 is the reading error that is within the error limit, 24 is the reading difference of the number value of the earthquake rank, 25
is the reading difference of the end signal.

3 is a functional block diagram showing the configuration of an embodiment of the present invention, 26 is an FSK @ modulated digital signal;
27 is a signal reading value, 28 is a demodulator, 29 is a detection unit,
30 is 9 parts of signal value reading, 31 is the number of stitches of signal reception, 5
2 is a signal j-position detection and display unit.

In FIG. 5, the FSK modulated signal is demodulated in a demodulator 2B to produce a digital signal 26.

The FSX demodulated nine-digital code 26 is input to a detection section 29, where the original signal sequence and signal value are detected.

The signal value reading section 30 reads whether the input signal is dl'' or 'o''. )
When the signal value has changed to 1, the signal value reading unit 50 detects this and sets the count value of the signal reception count unit 51 to 0. That is, this point is regarded as the beginning of the start signal (FIG. 2, 12). Therefore, the range δ, A (=(head detection time)−(
When the input signal reception interval is T, the signal value change time) is as follows (Equation 11 O over p).

0 ≦ 6 Todoroki < y
Thereafter, each time the signal value reading section 30 receives -11 of the input signal, it adds 1 to the count value of the signal reception count stitch count section AI, and the count value of the stitch count section 31 becomes the next (2). ) When the value mJ shown by the formula is reached,
The signal value reading unit 60 confirms that the signal is a start signal (the number 1 value is 10) and sets the count value of the signal reception number stitch count unit 510 to 0.

淋a=[(time width of one signal)/2xr) (2) Here, [] is rounded down to the decimal point.

At this time, the range J# (=(signal value reading time) - (temporal center position of the signal)) of the reading error of the start signal value (Fig. 2, 19) is T (time for one signal, length)/2X (signal reception interval)) "(C)" is the decimal part) is smaller by l, which is the result of Equation 31.

−T・[(time width of one signal)/2XT: l*≦J.

<T・(1((1 signal time m)/2xr)1・

(3) where () is the decimal part.

Thereafter, each time the signal value d taking unit 60 receives the input signal 11'', it adds 1 to the count value of the signal reception number stitch count unit 31, and the count value of the count unit 61 is expressed by the following equation (4). When the indicated value 'IRQ' is reached, the signal value reading p section 30 reads the input signal value and generates an output, and also sets the count value of the counting section 61 to zero.

mD = [(time width of 1 value) / T :l
(4) ζ where [ ] is rounded down to the decimal point.

The output of the signal value reading section 30 is ANDed with the output of the Kosuke number reception count section 61, and the signal value of the first order is output at the time of reading the number of numbers of the Hirosuke number (FIG. 2, 14). arise. The signal rank detection and display unit 32 displays the signal value of the first rank on the 11111th rank signal output terminal by counting the number of outputs of the signal value output. This display is maintained until the signal values of all ranks are displayed. 5 In this case, the first order signal value reading error (Fig. 2 20)
The range δt (=No. 1 value resistance time) - (temporal center position of the signal)) is the reading error range of the start signal value - aIIc
Ratio, r ((1-No. O time wheel) / (1-No. reception interval))
*(()"if small a part) is smaller, the formula (5) is passed.

-T・1 [(1 value time width/2xr:]*+(4@
time width of issue)/T〕town≦J, <'I・1t−((11
signal time width)/2 X (signal reception interval)] 1-C1m
(time width of the signal)/(signal reception interval)] By repeating the same operation, the signal values from the second rank onwards are output to the output terminal of each rank of the signal rank detection and display section 32. It is obtained sequentially, but when the number of repetitions reaches the maximum n times (jl is an integer) that satisfies the following equation (6),
The reading error is very close to the difference limit (Figure 2 21),
If the same IIIJ operation is further repeated, the small reading error will exceed the error limit (FIG. 22).

1-T・[(Time of 1 value number m)/T)*≦Error limit value
(6) In order to prevent the reading error from exceeding the error limit, L in equation (6) must be
11N signal time width and error - (Since it is determined by the signal speed of the asynchronous 1M signal and the sampling rate of the digital signal, the signal value reading p@so will be the same as before after one reading is performed. The count value that increased by 1 compared to
Signal value reading fii
It is a good idea to configure lsl. By reading the signal value with the count value "D+1", the reading error Br・1t-(1
Time span of No. 1)/T)”Recover by I.

The only way to repeat the operation based on the count value m, + is as follows (7)
At the maximum number (the integer number) that satisfies the equation, the 载*b error again approaches the error limit very much.

Constant T
Error limit value (7) ζHere, 1 is the decimal part.

From then on, the signal value reading unit 30 again reads the signal value 9 after the counted value until the maximum m (s
is an integer).

By repeating the above-described operations, the signal values up to the No. 1 rank are displayed on the signal rank detection and display section 32. By reading these signal values as read values 27, the original signal sequence and signal values are detected. Next, the signal value reading section 60 detects the end signal (signal value is ql).
” is detected (Fig. 2, 17), the signal rank detection and display section 32 resets the signal value of each rank and the needle value of the signal rank, and returns to the initial state. Then, the signal value reading section sO signal reception number stitch count section 510 stops the stitch count operation and waits for the detection of the next start signal.

In the case of a 30G&/A asynchronous binary signal and an 8KHz sampling input signal, the values of each parameter shown in equations (1) to (7) above are as follows:
.

The reading error can be within 5 degrees. That is, 0 ≦ J, A < 125 Pm
(8) tx, 613 (9
1-41-5pm: fhJ# < 83-5 Pa
@・5Dz24
11')-125μm≦J, <0.5/J#
all = 1
AS lecture = 2 11
As explained in detail about the invention, the method of the present invention performs detection by changing the signal value reading time interval per sampling period, so that the reading error can be made smaller than the signal reception interval. It has the advantage of being able to (9) Although the operational logic of this method can be realized with hardware logic using integrated circuits, it is easier to implement because one operational logic can be defined as a program using a signal processing circuit for digital signal processing. can be realized.

By adding a signal processing device having a signal value detection function according to the method of the present invention to a digital exchange, it is possible to receive a psi-modulated asynchronous signal from a data terminal or the like without converting it into an analog signal.

[Brief explanation of the drawing]

Fig. 1 is a conventional circuit operation diagram for signal detection of continuous non-binary signals - 1°, Fig. 2 is an explanatory diagram showing the operation in an embodiment of the present invention, and Fig. 6 is an embodiment of the present invention. FIG. 2 is a functional block diagram showing the configuration of FIG. 1...Input signal, 2--Start signal, 6...111th
i1st position O signal, 4-21st [position signal, 5-@s
9th signal, 6--end signal, 7- temporal center position of start signal, 8--1st J1 position o@4#o temporal center position,
9--Temporal center position of the second-order signal, 10--Temporal center position of the second-order signal, 11--Temporal center position of the end signal, 12--Detection timing of the beginning of the start signal. ,1
3 - 9th timing for reading the start signal value, 14 - 11th signal value reading timing, 15 - 2nd order signal value reading timing,
16... Signal value reading of sJ[ 9th period, 17...
End signal value reading) timing, 18-...Detection error at the beginning of the start signal, 19--Start signal value reading WAi1°20-.
・1st order signal value reading error, 21-No. 2nd order signal value reading error, 22...-Reading error exceeding the difference limit, □r 25-Reading error within the error limit, 24- ...5ll11th place: '1 signal value reading nx difference, 25.-End-...,. Signal reading ii difference, 26-FSX decoded digital signal, 2F□Mitsu-''Q, No. 1 reading value, 28
-Recovery part, 29...Detection part, 30-...Signal value reading part, 31-...Number of signal reception times, number of stitches,! s2--signal rank detection and display unit. Patent applicant Nippon Telegraph and Telephone Corporation

Claims (1)

[Claims] Significance is a discrete signal obtained by sampling at fixed time intervals asynchronous signals that are serially transmitted from the beginning with two-chain symbols added to the beginning and end of a plurality of two-chain symbols to indicate the start and end of the signal string, respectively. When detecting the original signal train or signal chain from a serial 2FK Tsukuda, it is possible to detect the signal at appropriate time intervals starting from the center point of the start signal on the time axis without converting the signal into a continuous signal. A method for detecting a value, comprising a means for changing the time interval of the signal value g in accordance with a change in the gauging error of the signal value, in units of a sampling period, An asynchronous signal detection method characterized by detecting a signal value such that the signal value falls within a certain value.