JPS5897986A - Signal discrimination system - Google Patents

Abstract

PURPOSE:To eliminate the need to send out a test signal, etc., and to minimize an error in signal discrimination by calculating the code error rate of multiplexed code information itself during a vertical blanking period. CONSTITUTION:An input digital signal 41 is sent to a discriminating circuit 45 together with an optimum clock signal obtained from a switch circuit 44. The discriminating circuit 45 supplies encoded information to a signal processing part 53 as a digital signal 47 by a threshold level 50. The signal processing part 53 extracts a framing signal, etc., from the input digital signal 47 and sends them to an operation processing part 48 in parallel. The processing part 48 calculates the total number of a bit group of each unit of the encoded information and the number of errors and then adjusts a threshold level output 51 so that the error rate decreased. Consequently, code errors are minimized without transmitting a special signal such as a test signal.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a signal identification method for identifying coded information signals such as coded character information signals that are multiplexed and transmitted during the vertical retrace period of a television signal, and in particular, the present invention relates to a signal identification method for identifying coded information signals such as coded character information signals that are multiplexed and transmitted during the vertical retrace period of a television signal. This system is designed to minimize errors in signal identification by adjusting the signal identification means t based on the code error rate of the received and demodulated coded information signal itself, without having to send out any special signals such as sending out the coded information signal. be.

The above-mentioned encoded character information signal for teletext broadcasting, which is suitable for applying this kind of signal identification method, generally has a %#J/
It is configured in the form of a packet signal as shown in the figure and is multiplexed and transmitted. That is, in the configuration shown,! and J are
They are a horizontal synchronization signal and a color burst signal in a normal television signal, respectively, and J is an encoded text information message consisting of, for example, an NRZ signal multiplexed for teletext broadcasting, and the clock timing t on the receiving side is set. The clock run-in signal is also used to set the frame timing. and teletext data signal 4 ◎The teletext data signal t is usually a pattern that transmits digital signals of ・ln and *Qvi obtained by eating figures and characters in their original form. It is configured depending on the transmission method.

In addition, the display color, display format, layout, program name or program number of teletext broadcasting, service, format job information when displaying information such as figures and characters, and even the page number and line of text information display. Numbered information display control signals are generally transmitted as dedicated packet signals or arranged at specific positions in packet signals, but transmission errors may occur in these information display control signals. When this occurs, it has a significant effect on the information display mode, so the code signals that make up these control signals are added with bits for error detection and correction, for example, so-called (t, 4c) extended Hamming. By using a code tube, a block error detection/correction bit is added to the information bits of the relevant bits./A code signal of 1 bits is ignored, and 1 bit error correction and 1 bit error detection are performed. When decoding a code signal of such a code format, if the phase and level comparison thresholds of the clock signal used for sampling are not appropriate, 1 bit error, 1
Code errors such as bit errors occur frequently, but if the phase and level comparison thresholds of the clock signal are appropriately set, code errors can be eliminated, or at least minimized. Considering the frequency of code errors occurring in the code signal of l bits of l block described above, that is, the error rate, when the bit error rate due to the mixing of random noise is P, the code signal of /pro oct pits /
The probability that a bit error occurs P is a binomial distribution of 1.-J in 8C1 P (1-p), and the code signal KJ bit I!! of I block l bit is also The probability P2 of occurrence is a binomial distribution of Jtp2 in '2''@C2・p''(1-p)'. Therefore, the bit error rate p is p << 1
If so, p>, >p, and almost all code errors caused by random noise mixed into the l bit code signal are l bit errors, and the granularity of occurrence of 2 bit errors is is extremely small, and the frequency of occurrence of J bit errors is on the order of a, -p, so it is even smaller and can be ignored.Moreover, as mentioned above, the code signal of the /block l bits is (r , p) If it is an extended bagging code, it can be detected in its l-bit error tm*, so (tra4A>For an extended bagging code, the number of times the decoding routine has been passed and the number of blocks in which the error was detected, that is, / If you constantly count the number of bytes when a block is pitted, calculate the ratio, and constantly monitor the code error occurrence rate, you can determine the extent to which code errors occur at each point in time. It will be possible to understand.

Furthermore, detection and correction of code errors are described above.

・The expansion/1-ming code that can achieve the following effects (see 1.) is included in the transmission of coded information signals for teletext broadcasting, etc., which are actually planned to be used. Examining whether there is one, the encoded information signals for teletext are each composed of is / (number of decimal types as shown in Fig. 1) (in other words, in the illustrated configuration) , //d is a code signal for service identification and interrupt control that is commonly added to the beginning of each packet signal, and l is a data identification code for identifying each packet signal. Each of the code signals illustrated by the code l, ie, the page control packet signal pcp.

Color code packet signal cap, pattern data/packet signal PDP, horizontal scroll full data packet signal
- HDP, program index packet signal PIF, and dummy packet signal DMP can be identified.

As shown in the figure, the page control packet signal PCP has program number/3. Page number 14I- and display
Control data l for controlling the entire page regarding erasure etc.
! All of them are configured with extended hanging codes (res), but the second half of the three bytes is not normally used. In addition, the color code packet signal ccP#'i, the display color of the sub-blocks representing the area of one character - is displayed in one line, NO,! Color specification data 1 specified for the 91-line J/Subpuden footer as a character
The color specification data /4 consists of J/byte (#, reference) expanded Hamming code.
In addition, the pattern data packet signal FDP is a digital signal obtained by scanning the screen of characters and figures.
Pattern data forming lI/7 seconds, usually
Character information is transmitted in 7 character nobu X/l bits, so
Eleven pattern data packet signals FDP are transmitted for every seven lines of character information.

Further, the horizontal scroll data packet signal HDP includes the same program number /I as in the page control packet signal PCP described above, scroll control data /P instructing to stop and update horizontal scrolling of character information display, spare byte -〇, and The above pattern data packet signal FDP
It consists of the same pattern data as in
Among them, program number /I and scroll control data 1
2 is composed of (r, l'Jft large hao/g code).Furthermore, the program index packet signal PIF is
The serial number of the program index packet and the remaining JO bytes are the broadcast program numbers for the /j program.
..., Jj, all of which are <t,
U) It is composed of an extended Hamming code.Furthermore,
As for the packet signal DMP, as mentioned above, the amount of information of the teletext program to be transmitted in the nine series of packet signals varies depending on the program, so the total number of bytes per seven programs should have some margin. Normally, all bits are set to 1.As is clear from the above, the first 11 of each packet signal is , 7-byte service identification
A code signal // for interrupt control and a J-byte data identification code /J are added, and each of these 3 bytes is composed of B, cf.) expanded hatching codes, so each packet signal 1. Since the (f, ≠) extended Hamming codes of at least J blocks are included, it is possible to easily and reliably monitor code error9 occurrence status in code signal transmission using these (re 4') extended Hamming codes. To automatically adjust a signal identification means so as to suppress the occurrence of an error in identifying a coded information signal without transmitting a special signal for detecting the occurrence of an error as in the conventional method. On the other hand, the signal identification device conventionally used for transmitting this type of coded information signal is configured as shown in Figure 3.
In the figure, j/ is an input digital signal, which undergoes various waveform assimilation depending on the characteristics of the transmission line, and is suppressed to a certain extent by the automatic gain control side of the receiving device, but the level change It is customary to receive the same. Also, here is a reproduced signal, which is reproduced from an input digital signal using, for example, an automatic phase control circuit. Further, JJ is a delay circuit for delaying the phase of three clock signals to adjust them to a hazy phase suitable for identifying input digital signals, and sequentially extracts delayed clock signals with different delay amounts, The appropriate phase delay clock signal tube is selected using the changeover switch J# and the identification circuit J! #l'i is a potentiometer to which a constant DC voltage V is applied,
C Threshold voltage tube identification circuit with an appropriate level necessary for identification by level comparison of input digital signals J! supplying to
Therefore, the identification circuit 31 is supplied with a clock signal of an appropriate phase manually selected by the changeover switch Jhiro and an appropriate threshold level manually adjusted by the counter/geometer Jt. By comparing the level of the input digital signal sampled at the appropriate time with the appropriate threshold level and removing the shadow* of the level change during the waveform change, the input digital signal level @7m and @Q* can be identified without error and accurately. However, in the conventional signal identification (b) path with such a structure, as described above, the clock phase and threshold value used for sample identification of the input signal waveform level are Since all levels are set by manual adjustment, changes in the clock phase and threshold level due to changes in the delay amount of delay circuit JJ and changes in potentiometer #ID1i's ambient temperature, or changes in the input signal level itself. It is said that it is not possible to readjust the amount to an appropriate state by following level fluctuations caused by fluctuations or changes in transmission line characteristics, and therefore errors are likely to occur in the identification of input signal levels of /n and @Qn. Disadvantages: The purpose of the present invention is to eliminate the above-mentioned conventional drawbacks, and to take advantage of the special effects obtained by applying the 7'h (r, 4) expanded Hamming code. The state of code error occurrence in the encoded information signal itself to be transmitted without adding a special test signal I! It is an object of the present invention to provide a signal-specific system in which the operating conditions of the signal identification means can be automatically adjusted so as to constantly monitor the error rate and minimize the error rate.

That is, the signal identification method of the present invention distinguishes encoded information signals from one
In the signal identification method, the coded information signal is sequentially identified for each period of a predetermined length, and the coded information signal is identified in each morning. The total number of bit groups and the number of errors in the unit in the encoded information signal are calculated to calculate the code error rate of the unit, and the code error rate of the unit calculated in each period is calculated in the unit calculated in the immediately preceding period. The threshold level and the phase of the clock signal are changed and set in a direction in which the code error rate of the unit decreases based on the result of comparison with the code error rate of the unit. be.

The present invention will be described in detail below with reference to the drawings. First, in order to achieve the above-mentioned nine objects of the present invention and take advantage of the above-mentioned features of the present invention, a clock used for signal identification will be described. An algorithm according to the invention for controlling the phase and threshold level is illustrated in flowchart form in FIG. Therefore, as mentioned above, at least 3 bytes of (1,4c+extended Hamming code) are always included in the 3≠bytes of each packet signal in the encoded text information signal of the teletext hanging rod shown in the second figure. Therefore, each received packet signal is subjected to the (r,p) extended Hamming code decoding algorithm.In other words, in the flowchart shown in the figure, first, in step 81, Decode the (r, 41+l expansion) ming code forming the code signal part of each received packet signal,
In step S2, the total number of bytes of the decoded code signal and the number of bytes that have code errors among them are counted. In step S3, the counting result is determined, and the number of decoded bytes examined is If the predetermined value n has not been reached, no control is performed to change the operating conditions of the signal identification circuit, and the next packet signal is waited for in that state until the number of test bytes is reached. If the predetermined value n has been reached, in step S4, the byte error rate is calculated from the number of check bytes and the number of error bytes, and it is determined whether the byte error rate at that point has reached the predetermined value r. Determine. As a result of the determination, if the byte error rate has not reached the predetermined value r, it is assumed that the code error occurrence rate determined by the signal discrimination conditions at that time is within an allowable range, and a series of It is judged that the book has been adjusted. Regardless of such a judgment, it is possible to repeatedly adjust the signal identification operating conditions, and by lowering the above-mentioned predetermined value r, which is the basis for judgment regarding the suitability of the byte error rate, by /step. , a more rigorous judgment is made to determine the signal identification operating conditions, i.e.
The above-mentioned optimal values of the clock phase and threshold level can be adjusted with even higher accuracy and the adjustment can be repeated.

As a result of the above-mentioned judgment, if the byte error rate reaches or exceeds the predetermined value r1, the clock phase and threshold compensation level are adjusted as described above in order to reduce the byte error rate. We will perform key 41,
In step SS, the number of repetitions of this Ill11 is determined, and if the number of repetitions has reached the predetermined value 1B2, in step 811, it is determined that a series of adjustments have been completed, and the required signal identification is performed. Completion of adjustment of operating conditions - On the other hand, as a result of the above-described determination, the number of repetitions of #J4!1 did not reach the predetermined value ax K, and therefore, it was determined in step 86 that the threshold level adjustment was appropriate. #″t in case
1t1 Step 8 The current byte error rate is compared with the byte error rate calculated for the previous signal identification to determine an increase or decrease. If the byte error rate has increased from the previous time, step 88 , it is determined that the direction of the clock phase and threshold level adjustment at that time was the opposite direction to reducing the byte error rate, and the threshold level of these signal identification operating conditions is adjusted according to the previous adjustment. Step S
In step 9, the number of chattering up to that point is determined, and as a result of the determination, if the number of chattering has reached a predetermined value, KFi, in step 810, at least the threshold level has been adjusted to the required number of times. Therefore, it is determined that the process has ended, and the threshold level set at that time is determined to be the optimum value, and the process moves on to adjusting the clock phase. If the result of the above judgment is that the number of chattering times has not reached the predetermined value, the threshold level must be adjusted again.On the other hand, as a result of the judgment in step 87, the byte error rate is lower than the previous value has decreased, it is determined that the direction of adjustment *a was appropriate, and in step 817, the threshold level is changed by one step in the same direction as in the previous adjustment, and then the threshold level is changed. Steps 87 to 810 and S17 will be repeated as described above.
When the adjustment of the threshold level is completed in step 812 to
At 816, for the clock phase, by a k −f IJ sum exactly as applied for the threshold level,
Make adjustments to obtain the optimal value.

In addition, when calculating the byte error rate for the first time, both the threshold level and clock phase are set to appropriate values and the above algorithm is started, and from the second time onwards, they are changed by 7 steps in either direction. shall be allowed to do so. Furthermore, it is optional whether to adjust the threshold level or the four-phase phase first.Furthermore, the signal identification operating conditions can be adjusted or set using the above-mentioned algorithm as soon as the power to the signal iron cover is turned on. It can be carried out at any time, for example, when switching between the encoded information program itself or its encoded information document to be multiplexed and transmitted, such as a television broadcast program, or at any time during the reception of the encoded information signal. It is also possible to designate the adjustment timing from the receiving side according to the error occurrence situation in the encoded information signal.Next, the signal identification operating conditions can be adjusted or Configuration example of a signal identification device that allows automatic settings 'frs! Each component in the j-th illustrated configuration shown in the figure/4c
J, 7. at, l, ≠7 are each component j/, JJ, JJ in the conventional configuration shown in the third figure.

71, 74, and 77, respectively, and represent an input digital signal, a clock signal, a delay circuit, an identification circuit, a potentiometer, and an output digital signal, respectively. The component m- added to #9 in the configuration shown in the first figure is a switch circuit made of, for example, a semiconductor switching element, and is the manual changeover switch J4! in the conventional configuration shown in the third figure! 4, corresponding to the control signal SFK from the arithmetic processing unit at, which is constituted by a so-called microprocessor, switches the delayed clock signal supplied from the delay circuit J, and selects the delayed clock signal with the optimum phase from the identification circuit. On the other hand, the threshold level was set by manual adjustment of the potentiometer 4. Threshold level DC voltage DC addition circuit jJ
In addition to supplying K, the analog control voltage from the digital/analog converter built into one arithmetic processing unit pi is supplied.
- The DC adder circuit jJ K is supplied, and the threshold level voltage in the form in which the initial voltage value is corrected by the control voltage value is supplied to the discrimination circuit Yume j. Therefore, the discrimination circuit -! Both the phase and the threshold level used to differentiate the level of the input digital signal waveform in 1141 are automatically obtained by control information from the arithmetic processing unit $t.However, in the configuration shown in FIG. Added component 1
1 is a signal processing section, and a job-specific circuit 4! -! Based on the output digital signal -7 from the output digital signal -7 and the delayed clock signal j4' from the delay circuit 447, the input digital signal≠l
The processing output signal 11, which is obtained by extracting a flaking signal indicating the timing of the beginning of the signal and the like and collecting these signals in parallel, is supplied to the arithmetic processing unit Yume t. In the arithmetic processing unit D, the processing output signal ! ! When the above-mentioned signal identification operating condition control information is formed by performing appropriate arithmetic processing N'ft on 4, the processed output signal ! ! Write the output digital signal 7 in the built-in random access memory and hold it. As described above, the signal identification II shown in the third figure is performed by the method of the present invention.
An example of a specific configuration of the calculation part that forms the main part of N is shown in #1.
is shown in the figure. In the illustrated configuration, among the processed output signals jI from the signal processing unit 11 in the configuration illustrated in the third figure, the output digital signal 11 is guided to the writing decoder 47 and included therein (l.

≠) Decode all extended Hamming codes, and generate an error counting pulse each time an error is detected in those (r, 4g) extended Hamming codes. - Extract the code from the decoded output signal of the Hamming decoder 4J. Circuit t! 4 of the control signal generation circuit tr that generates various control signals based on the processing output signal jj Q:) framing signal 4Jt'', the decoded output signal 4 (t, ge) enlarged humming Extract only the encoded part and use the extracted output signal as a gate signal to the gate circuit 47.
is applied, the above-mentioned error counting circuit 14 generated by the Hamming decoder 4J is gated and taken out, and the counter 4
By supplying and counting the number of occurrences of the (r, 4c) extended ... timing code KJI included in the reproduced output digital signal 1/ and the number of 1-bit errors, , the counting period M of the number of error bytes
is determined by the extracted output gate signal of the code extracting circuit 4j, which is determined under the control of the control signal generating circuit 41. When the counting period has elapsed, the number of error bytes at that point, which is the count output of the counter jP, is stored in the register 70, together with the previously counted number of error bytes in other registers 7 that have been transferred from the register 70 and stored. , the number of error bytes at that time is supplied to seven comparators and compared with each other, and according to the result of the comparison, the signal identification operating conditions are set according to the algorithm shown in Figure 1. Generate rounding control information signals for adjusting the direct level under the control of the control signal generating circuit at. That is, the comparator 7J controls the addition/subtraction of the count value of the up/down counter 73 according to the increase/decrease in the number of error bytes by comparing the number of error bytes before and after, and the comparison result of the increase/decrease in the number of error bytes is controlled. It also leads to a chattering detection circuit 7H to detect the occurrence of chattering in the signal identification operating condition setting described above, and stops the counting operation in the up/down counter 7J in response to the detection of the chattering.

The count output of the up/down counter 7J, that is, the information on the increase/decrease in the number of error bytes is sent to the register 7! The information is stored once in the memory, and then read out and guided to the selection circuit 74 when setting the signal identification operating conditions, and is used as v4 copy number increase/decrease information depending on whether the threshold level is adjusted by the algorithm shown in the figure or the timing phase is adjusted. The up/down counting output is switched and supplied to the digital/analog converter 77 or the switch selection circuit 7t, and a DC control voltage for threshold level correction is supplied, respectively! 1 or a switching control signal of the switch circuit $1 is generated.

As described above, in the signal identification method of the present invention,
For example, if an (r,p+extended C code is used in the configuration of the encoded information signal, it is possible to detect and correct an error in the signal waveform identification of the encoded information signal). )
The signal identification operating conditions are automatically corrected to the optimum state based on the results of constant measurement of the byte error rate of the extended Hamming code. (See 1.) Determined by the appearance frequency of the expanded Hamming code @Therefore, regarding the encoded character information signal with the configuration shown in Figure 1 for teletext broadcasting scheduled to be implemented, (f, see) the appearance of the expanded Hamming code. Examining the frequency - Therefore, the text information on the 1iji side in scheduled teletext broadcasts is usually the page control packet signal PCP of the l packet, the color code packet code CCP of the /7 packet, and the pattern data file of the /13 packet. It consists of a total of /7/ packets consisting of 1-bit signal FDP, of which the page control packet signal PCP includes //block, color code packet signal c
cp 6c contains the (#, 4C) expanded Hamming code of the J da block, pattern data packet signal PDPKFiJ block. Therefore, the total number of (r, e) extended Hamming codes in the coded character information signal for '1iii planes is // x / + J reference x /7 + j
x /11 = /, 04!1 block, l#
The limit on the accuracy of measuring the byte error rate during the period of rz seconds, which is the required transmission time of the encoded character information signal for one screen, is approximately 10. -1,048 On the other hand, in order to maintain the quality of teletext service at the required level, the permissible bit rate for encoded character information signals is approximately IO, and this is defined as approximately IO. When converted into a block error rate, it is approximately IO. Therefore, during the above-mentioned next transmission time J, jt of 1 second, when the (r, p) extended Hamming code of the /, Our block is transmitted, on average there will be about 100 errors for the (r, l extended Hamming code). This is especially true if it is allowed to occur.

Therefore, the above-mentioned allowable bit error rate is set for bit errors that occur due to the mixing of normal random noise, and this allowable value is set for bit errors that occur due to the mixing of impulse noise. Judging from the extent of the impact, it is expected that the impact will be reduced by half, and regarding block WA due to the inclusion of impulse noise in teletext broadcasts, Ko,! Approximately in a period of seconds! Errors are allowed to occur for the (1,44) extended Hamming code of the 0th block. Therefore, errors are allowed to occur for about 100 blocks in a period of Jjt seconds. In order to measure the error rate based on the impulse noise that is allowed for about 10 blocks with a measurement accuracy comparable to the above-mentioned limit value lθ of the error rate measurement precision, it is necessary to , that is, approximately 7.1 seconds, and in areas with low error rates where the frequency of block errors is reduced, even longer measurement times are required.
As shown in the figure, in each packet signal that constitutes the coded character information signal tube, only the first J bytes of each must be composed of (r, 4') extended Hamming code t-4. It is conceivable to measure only the first 3 bytes of each packet signal, each of which has a 3≠byte configuration, but even in such a case, in order to maintain the measurement accuracy of the above-mentioned limit value, it is necessary to Next, another configuration example of the signal identification device according to the method of the present invention is shown in FIG. 7. In the configuration shown in FIG. It is possible to time-efficiently adjust or set the required signal identification operating conditions by increasing the error occurrence rate. , the error rate can be accurately measured in a short time even for code signal identification in areas where the aperture ratio of the so-called eye pattern is large, while maintaining the same measurement accuracy under the same constraints, and the signal identification operating conditions, that is, This allows the Kutsk phase and threshold level to be automatically adjusted to optimal values. That is, in the illustrated configuration, tl is an antenna input signal on which teletext signals are multiplexed, rJ is an attenuator group,
13 is an input/output changeover switch for the attenuator group, reference is a changeover control signal for the changeover switch IJ, rz is a high frequency circuit, l≦ is a detection circuit, and input from the detection circuit 16 in the configuration example shown in the first figure. Digital signal 1 is taken out,
The identification circuit that supplied that input digital signal≠! The configuration hereafter is completely the same as the configuration example shown in the first figure, and the above-mentioned switching control signal t# for the switch is assumed to be supplied from the arithmetic processing section or.

In the signal identification device having the configuration shown in the figure, the attenuation amount of the attenuator group rJ is set to an appropriate initial value by controlling the changeover switch IJ at the same time as the power is turned on, so that the pit error rate based on random noise is about 10. If the reception state is equivalent to a strong electric field and the detection output digital signal 7 is adjusted in accordance with the algorithm shown in TLC41C in such a reception state, the required measurement time will be 1/1/2 of the above-mentioned required measurement time. It is possible to perform high error measurement with the same accuracy in a short time of about After completing the setting of the signal identification operating conditions in the above-mentioned mode, the attenuation amount of the attenuator group t is returned to zero, and all actual signal identification is performed under the best reception condition. *It goes without saying that the settings can be made at any time, such as when the power is turned on, when a control command is received from the receiving side in response to an error occurrence situation, or when switching reception channels. By reducing the signal-to-noise ratio as described above, the measurement can be carried out in a time-efficient manner.
I! This value is calculated assuming that seven packets of the coded cultural information signal are multiplexed and transmitted during the signal's vertical retrace period, and the coded character information signal is transmitted at a transmission rate of l,Q buckets per second. However, if a plurality of N packet signals are multiplexed and transmitted during one vertical retrace period, it is naturally possible to reduce the required measurement time to t4.

As is clear from the above description, according to the present invention, when identifying the signal waveform on the receiving side of the encoded information signal, the encoded information signal to be transmitted can be transmitted without the need for the transmitting side to specially send out a quantitative signal. By applying (1,4/-) expanded Hamming code to the coded information signal, the state of occurrence of code errors can be grasped accurately and quickly at all times, and based on the measurement results of the code error occurrence rate. Operating conditions for signal waveform identification,
In other words, it is possible to automatically adjust the phase and threshold level so that signal identification can always be performed under the best conditions without error, and furthermore, such automatic adjustment can be performed with a relatively simple circuit configuration. be able to.

In addition, in a state KL in which the input signal-to-noise ratio of a teletext signal is intentionally lowered by inserting a reducer, and in a state 1- in which the error rate is intentionally increased, the error rate decreases per meter in a relatively short period of time. #1 Since it can be used in areas with strong electric fields, it has a good signal-to-noise ratio and a low error rate, making it possible to accurately measure the error rate in a short time even when normal measurements take a long time. can be measured and automatic adjustment of signal identification operating conditions can be quickly performed.

In the above explanation, signal identification was performed based on the case where the encoded information signal partially included (r, +1 extended Hamming code), but it is assumed that the entire information signal is encoded. Of course, similar effects can be achieved by applying the signal identification method of the present invention to character code broadcasting, liftware broadcasting, or general data transmission. The code signal included in the code signal is not limited to the above-mentioned 9B, p) extended Hamming code, but may also include (/j, //) extended Hamming code, shortened cyclic code, convolutional code, etc. As long as it is a code signal whose degree can be ascertained, it can be included in the coded information signal in the same way as described above to achieve the same effect.

[Brief explanation of drawings]

#11 Figure shows the coded character information signal for teletext broadcasting.
Signal waveform diagram showing multiplexing mode for broadcast signals, 1st
The figure also shows a diagram showing a configuration example of various packet signals constituting the encoded character information signal, a block diagram showing the configuration of a conventional signal identification device under Category J, and a block diagram showing the configuration of a signal identification device according to the conventional system under Category J. 7a-chart showing the Nt of the signal discrimination overrange;
1 is a block diagram showing an example of the configuration of a signal identification device according to the method of the present invention, FIG. FIG. 2 is a block diagram illustrating another configuration example of a signal identification device according to the present invention. l...horizontal synchronization signal, co...color burst signal,
J...Encoded character information signal, Reference...Clock run-in signal,! ...7-level switching signal, 4...data signal, //...service identification/interrupt control code signal,
Heto...Data identification code signal, /3...Program number,
ll...Page number, lj...Control data, /4.
...Color specification data, 17...Pattern data, ll.
...Program number, IP...Scroll control data, KoO
...Spare byte, here...Pattern data, here...
・Serial number, ko J, ko san. λ! ...Sending program number, ko4...preliminary part, 3/...
・Input digital signal, here...clock signal, 3J
...Delay circuit, 3 Hiro...changeover switch,! !・・・
・Identification circuit, 3≦...potentiometer, J7...
Reproduction output digital signal, 4I/...input digital signal, Guco...clock signal, Reference J...delay circuit, Reference≠...switch circuit,
≠!・・・Identification circuit, reference t・・・Potentiometer, ≠
7... Reproduction output digital signal, at... Arithmetic processing unit, jl... Analog control voltage,! -... DC adder circuit, 11... Signal processing unit, j-... Delayed clock signal, 11... Processed output signal, 41... Reproduction output digital signal, tco... 7-ray Construction signal, ≦3...
・See Hamming decoder...Decoded output signal, 41.
...Sign extraction circuit, 44...Error counting pulse, 17.
...Gate circuit, 11...Control signal generation circuit, 4F.
... Counter, 7θ, 7/, 71... Register, 7... Comparator, 73... Up/down counter, 7%... Chattering detection circuit, 74... Selection circuit, 77... Digital to analog converter, 7t...
・Switch selection circuit, II...antenna input signal on which teletext signals are multiplexed, t, 2...attenuator group, lJ...changeover switch,
ll...switch control signal, fj...high frequency circuit,
14...Detection circuit. Patent Applicant Japan Broadcasting Corporation No. 11: (['1 Figure 2 Procedural Amendment April 2, 1982 1, Indication of Case 1982 Patent Application No. 195548 2, Title of Invention Signal Identification System 3. Relationship with the case of the person making the amendment Patent applicant (435) Japan Broadcasting Corporation 1, the specification letter page 1, line δ to page 8, line 8 are corrected as follows: ``8. Claims signal is sampled by a black signal of a predetermined phase and compared with a predetermined threshold level to sequentially identify im* for each period of a predetermined length, and the encoding identified in each period. The total number of unit bit groups and the number of errors in the information signal are respectively counted to calculate the single code I!I9 rate, and the code error rate of the unit calculated in each period is calculated as the code of the unit calculated in the immediately preceding period. A signal identification method characterized in that the threshold level and the phase of the click signal are changed and set in a direction in which the code error rate of the unit decreases based on the result of comparison with the error rate. .Turtle: The signal-to-noise ratio of the information signal is once lowered and restored after setting the − value level and the phase of the clock signal, respectively. Signal identification method ◇", 2. Lines S to 9 of the second part of the specification include "For example, 51i1, which includes encoded information signals such as character information signals that are multiplexed and transmitted.
[Regarding the signal identification method for identifying the level information signal, in particular, it is based on the code error rate of the coded information signal itself contained in the received and demodulated information signal without sending out any special signal such as sending out an adjustment test signal.] By adjusting the signal identification means, correct it to "signal", delete "encoding" in line 18 of the same page, and overlap line 20 of the same page, for example, characters that are at least partially coded by NRZ signal. Corrected to "information letter." 8. Between the 8th line and the 4th to 5th lines, it is composed of, for example, an 8-value information signal such as a data signal and a data signal 6 for text broadcasting. Note that the data signal 6 for sending a character emblem is usually a graphic "L" obtained by scanning the characters "L" and "Bata" that transmits the binary information signal of "O" in its original form. ・1. "Food signal" 11 in lines 11-18 of the same page, line sθ
111 [line 8, 1117g line 12, line 18, 2
fi111! 14th line 1116 = 17th line galf place, 8th
Page 0 f8 [1st line, 4th line, 15th line, 18th line,
Page 24, line 1, page g5, line 9, s8, line 8, line 5, line 11, page 89, line 1θ, line 17, line 80
Page lines 6 and 7. Delete "encoding" on the 18th line. Correct "bit" in lines 14 to 15 of Kameoka No. 1 Summer to "r dot". γ Same page 9, lines S to 7 as follows: ``Using their (8,4) expanded Hamming code, we can expect to easily and reliably monitor and understand the state of occurrence of kneading during the transmission of the entire character information signal.
Corrected to ``Kneading occurrence detection'' as before. 8. Correct the lines 17 to 19 on page 10 of the same to ``Compare and identify the human digital signal levels "l" and "0" and reproduce the output digital.9. Page 11 of the same, lines 6 to 11. In order to reproduce the correct information signal, the delay amount of the delay circuit 88 and the adjustment amount of the gain 86 must be changed due to changes in ambient temperature, or fluctuations in the input signal level itself or the transmission line. It is necessary to readjust the clock phase and amam level to the optimal state by constantly following level fluctuations caused by changes in characteristics.
There is a drawback that it is impractical to make adjustments every time these changes occur. ” and changed lines 14 to 17 of the same page to “In addition, for example, the above C
3a4) By focusing on the special effect of applying a code such as an extended Hamming code that can be used to calculate the scissor rate, it is possible to utilize the special effect of applying a code such as an extended Hamming code, which is included in the information signal to be transmitted, without adding a special test signal. The coded information signal itself is corrected to ``occurrence of code 1''. 10, same page 13, line 11-5: ``In other words, the signal identification method of the present invention samples at least an information signal rich in encoded information signals with a click signal of a predetermined phase and compares it with a predetermined threshold level. In the signal identification method, the encoded information signal in the information signal is corrected to ``. 11, page 17, lines 9 and 10, "encoding information" is deleted. 12 Correct "decoder" in line 8 of page 0 of the same page to "defuda". 1 Correct the negative lines 8 to 4 of s8 of the same title to [(s14) expansion of the text information signal using the configuration shown in figure S for planned teletext broadcasting.''0 14 same) In page s4, line 9, change ``If it happens, it will happen.'' to ``
will be done. ”, and line 8116 is corrected to ``Since the permissible value is relaxed, it will be used in teletext broadcasting.'', and ``Koninaru 0'' in line 19 of the same member is corrected to ``Koninari.''. 16, same No. 16 [Correct "Figure 4" in line 11g to "Figure 2" and correct "Digital" in line 119 to "Information J. Section 16, page 86, line 2)" Code ” to “Human Power 2@Information”
"Code" in the same 11th line was corrected to "Sign", and the 17th of the same summer
Correct "Ikou" in the line to "Imine". 17. On page 88, line 8, ``culture'' was corrected to the letter r, and lines 18 to li on the same page were corrected to ``The coded information signal itself molded into the information signal to be transmitted, without the need for If the state of occurrence of code modification is included in the encoded information signal, it will be corrected to (8, 4) J. 18. Correct "liftware" in line 14 of page 89 to "software". 19 , the omission on page 80 of the same page is corrected to ``Similarly to the above, the code signal is included in the multi-tube information signal of the pupil and the 4-value sono-ike, and the same effect is obtained.''0 Figure 6 of the 20 drawings. Correct as shown in the attached correction diagram / External 14Fk'W / Procedural amendments (April 8, 1985 1, Indication of the case 1982 Patent Application No. 195548 2, Name of the invention Signal identification system & amendment Relationship with the patent applicant (435) Japan Broadcasting Corporation 6 Subject of amendment Column 7 for detailed explanation of the invention in the specification
Contents of the amendment (as attached), 1. "Code signal" on page 8, line 18 of the specification is corrected to "code signal." 2. Correct "code signal" on the 16th line of the same page to "code signal". 8. Delete "encoding information" on page 17, line 10. 4 Delete "This allowable value is" on page 34, line 1s. 5. Procedural amendment dated April 3, 1980, page 6, r
ll! Delete the 4th line.

Claims (1)

[Claims] 1. In a signal discrimination method that identifies a coded information signal by sampling it with a clock signal of a predetermined phase and comparing it with a predetermined threshold level, the coded information signal is sequentially identified for each period of a predetermined length, and In each period, the total number of bit groups and the number of errors in the unit in the encoded information signal are calculated to calculate the unit code error rate, and the code error rate in the unit calculated in each period is calculated. The threshold level and the phase of the WII clock signal are changed and set in a direction in which the code error rate of the unit decreases based on the result of comparison with the code error seconds wheel of the unit calculated in the immediately preceding period. A signal identification method characterized by: 2. The signal-to-noise ratio of the encoded information signal is once lowered and restored after setting the threshold level and the phase of the clock signal, respectively.1- Signal identification method 0 according to claim 1 characterized in