JPH0262173A - Data processor - Google Patents

Abstract

PURPOSE:To improve the S/N of a signal group with a small number level superimposed on the signals with a large number level by reducing the noises of data in a horizontal or a vertical blanking interval obtained on a receiving side. CONSTITUTION:A television signal obtained by superimposing a data signal on the vertical blanking interval is inputted from an input terminal 1, and by using the vertical synchronizing signal detected by a gate signal generating part 2 as a reference, the gate signal to indicate the interval where the data signal is superimposed is generated. It is gated by the output of a generating part 2 in a level detecting circuit 3, the generating frequency of each level is measured over a data period, the level whose generating frequency is more than a value set beforehand is detected, stored into a memory, and outputted. A quantizer 4 generates a threshold value by the output of the circuit 3 one field before, the threshold value is set as the comparing level, the input signal is quantized by a quantizing characteristic with its output as the output of the circuit 3, the data in the gate interval is switching to the output of the quantizer 4 by a switching circuit 5, and produced. Thus, the S/N of the signal with the small level number superimposed on the signal with the large level number is improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a method for transmitting a teletext signal or a digitized audio signal into a predetermined interval such as a blanking interval of a multi-level signal such as a television signal. The present invention relates to a data processing device in a device that superimposes and transmits a signal group composed of a small number of levels, such as the above.

[Conventional technology]

An example of a signal with a small number of levels being superimposed on a signal with a large number of levels is a method of inserting a control signal into a section of an audio signal, or a method of inserting a control signal or data signal into a blanking section of a television signal, etc. There is. The case of a television signal will be explained below as an example.

In a television signal, a data signal such as a teletext signal or a control signal may be inserted into a horizontal or vertical blanking interval. In this case, these signals are 2
Often a value.

[The problem that the invention seeks to solve]

Equipment that compresses the bandwidth of television signals and transmits them reduces the average amount of information generated to a certain level or less in the hope that there will be less information in the horizontal or vertical blanking sections to ensure the quality of the television signal. However, when a data signal is inserted into the horizontal or vertical blanking section and its noise level is specified, the average amount of information increases because it is necessary to improve the transmission accuracy of the horizontal or vertical blanking section, and the average amount of information increases. The problem was that even the quality of the John signal deteriorated.

[Means to solve the problem]

The data processing device of the present invention is capable of processing a signal with a small number of levels, such as a teletext signal or a digitized audio signal, in a predetermined period, such as a blanking period of a signal with a large number of levels, such as a television signal. In a device that superimposes and transmits signal groups composed of the above-mentioned multi-level signals, means for detecting a section in which a signal group composed of a smaller number of levels is superimposed from the multi-level signals, and extracting and outputting the signal of that section. and a means for examining the level occurrence frequency distribution of the multi-signal output signal from this means and extracting a level exceeding a predetermined frequency of occurrence, and setting a threshold value for the extraction level from this means, The apparatus includes means for quantizing a signal to one of the above extraction levels and replacing it with a signal in that section, thereby reducing the noise level of the signal in the above section.

[Effect]

In the present invention, the influence on the characteristics of signals other than the horizontal or vertical blanking interval is minimized without performing special processing such as increasing transmission accuracy on the data signal in the horizontal or vertical blanking interval on the transmitting side. To suppress noise in data obtained on the receiving side in a horizontal or vertical blanking section.

〔Example〕

Embodiments of the present invention will be described in detail below based on the drawings.

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

In the figure, 1 is an input terminal. 2 is a gate signal generation section, 3 is a level detection circuit, and 5 is a switching circuit, which detects the section where a signal group consisting of a large number of small levels is superimposed from the signal of a large number of levels, and selects the section. This constitutes a means for extracting and outputting the signal. Further, the level detection circuit 3 constitutes a means for examining the level occurrence frequency distribution of multiple signals from the output signal from this means and extracting a level having a predetermined occurrence frequency or more. Reference numeral 4 denotes a quantizer, and this quantizer 4 constitutes a means for setting a threshold value according to the extraction level from this means, quantizing the signal in the above section to one of the above extraction levels, and replacing the signal in that section. are doing. And, it is configured to reduce the noise level of the signal in the above section.

Next, the operation of the embodiment shown in FIG. 1 will be explained. In the embodiment shown in FIG. 1, a case will be described in which data is superimposed on 10 lines of vertical blanking of a television signal.

First, a television signal in which a data signal is superimposed on a vertical blanking section is input to the input terminal 1. Then, the gate signal generating section 2 detects the vertical synchronizing signal and generates a gate signal indicating the section in which the data signal is superimposed on the basis of the vertical synchronizing signal. In the level detection circuit 3, the input signal is gated by the output of the gate signal generation section 2, the frequency of occurrence of each level is measured over the data period, and a level whose frequency of occurrence is equal to or higher than a predetermined value is detected, It is stored in a memory (not shown) and output. Next, in the quantizer 4, 1
The output of the level detection circuit 3 before the field generates a threshold value, this threshold value is used as the comparison level, and the output is used as the output of the level detection circuit 3.The input signal is quantized and cut using the quantization characteristic. The switching circuit 5 switches and outputs the data in the gate section to the output of the quantizer 4.

Figure 2 shows the level detection circuit 3 and quantizer 4 in Figure 1.
FIG. 2 is a block diagram of an embodiment showing extracted portions related to the above.

The level detection circuit 3 includes a gate circuit 30 that extracts a section in which a data signal is superimposed from an input signal;
From the output of N'! N matching circuits 31-1, 31-2, . counter 32-1゜32-2-
...32-n and these counters 32-1 to 32-n
It is composed of comparators 33-1, 33-2, .

Further, the quantizer 4 compares the input signal with the output of a threshold circuit 42 which stores a threshold value from the output of the level detection circuit 3, and uses the result to compare the input signal with the output of the threshold circuit 42, which stores a threshold value from the output of the level detection circuit 3. The memo IJ 34K selects the stored level and outputs it to the output terminal 43 as the output of the quantizer 4.

Here, if the outputs of the level detection circuit 3 stored in the memory 34 are A and B, the output of the threshold circuit 42 is (A
+B)/2, and the quantizer 4 has a threshold value of (A+B)/2.
)/2, resulting in a quantizer whose outputs are A and B.

In terms of time, the output of the level detection circuit 3 one field before is used for quantizing the next field.

FIG. 3 is a waveform diagram of each part used to explain the operation of FIG. 1.

(,) is the input television signal, (b) is the gate signal, which is a rounded signal that extracts only the data signal from the input television signal (,), and also removes the horizontal synchronizing signal. (C).

(d) is a data signal within one horizontal period of the extracted data signal, (c) is the input of the level detection circuit 3, and (d) is the input of the quantizer 40 after one field. (•) is the output of the quantizer 4, and compared with (d), it can be seen that noise is removed by the present invention. By inserting the data processing device according to the present invention into the output section of the band compression device, the S/N can be improved even if the S/N of the band compression device is poor.

Note that in FIG. 3, A and B are the outputs of the level detection circuit 3 stored in the memory 34 shown in FIG.
A+B)/2 is the threshold value, that is, the threshold circuit 42
This is the output of

In the above embodiment, the configuration shown in FIG. 2 was used as the level detection circuit 3, but the configuration is not limited to this, and the configuration shown in FIG. 4 may be used.

This counts the output of the memory 35 that stores the data of the vertical blanking section, the coincidence circuit 36 that outputs when the comparison level of the control unit 40 and the output of the memory 35 match, and the output of the coincidence circuit 36. The outputs of the counter 3γ and this counter 3T are compared with a predetermined level, and if the output is greater than the predetermined level, the memory 39
The controller 40 has a comparator 38 which instructs the control unit 40 to store the comparison level, and a control unit 40 which generates the comparison level and also controls read and write commands of the memory 35, reset of the counter 3T, etc. be done.

In this configuration, the frequency of occurrence of level N13 of the input signal is checked, and the frequency of occurrence for N levels is simultaneously stored in the check memory 39, and the frequency of occurrence for one level is stored in the check memory 39. , this is repeated N times.

and matching circuit 36. Counter 37. The comparator 38 is used N times with respect to the NS comparison level generated by the control unit 40, and the frequency of occurrence of the NS level in the input signal is checked, and this operation is performed by the next field. good.

As a result, the hardware scale can be smaller than the configuration shown in FIG. 2, and the S/N ratio of the signal group can be improved. In this embodiment, a two-level signal has been described, but the signal is not limited to this, and two or more levels may be used.

〔Effect of the invention〕

As explained above, the present invention is capable of adjusting the characteristics of signals other than the horizontal or vertical blanking intervals without performing any special processing such as improving transmission accuracy on the data signals in the horizontal or vertical blanking intervals on the transmitting side. Minimize the interference and reduce the noise of the data in the horizontal or vertical pushing section obtained on the receiving side. This has the effect of improving S of several signal groups.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention, FIG. 2 is a block diagram of the embodiment extracting the parts related to the level detection circuit and quantizer shown in FIG. 1, and FIG. FIG. 4 is a waveform diagram of each part to explain the operation of FIG. 1, and FIG. 4 is a block diagram showing another embodiment of the level detection circuit in FIG. 1. 2... Gate signal generation section, 3... Φ level detection circuit, 4... Quantizer, 5... Switching circuit.

Claims (1)

[Claims] A signal group consisting of a small number of levels, such as a teletext signal or a digitized audio signal, is superimposed on a predetermined section such as a blanking section of a signal with a large number of levels, such as a television signal. The transmitting device includes means for detecting a section in which a signal group consisting of a small number of levels is superimposed from the multi-level signal and extracting and outputting the signal of the section, and a signal from the output signal from this means. means for examining level occurrence frequency distribution and extracting levels having a predetermined occurrence frequency; and a threshold value is set based on the extraction level from this means, and the signal in the section is quantized to one of the extraction levels. What is claimed is: 1. A data processing device comprising means for replacing a signal in the section to reduce a noise level of the signal in the section.