JPH11205088A - Waveform shaping filter processor and its processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a waveform reshaping filter processor by which the times of arithmetic processings is reduced, at executing of a filter processing in a packet signal and a real-time processing is realized. SOLUTION: A packet generating circuit 11e which generates the packet signal provided with a specified pattern in a packet head registers the numerical values of filter characteristics corresponding to all patterns in a table, which can be obtained within a data quantity that have been previously decided in the packet signal, before superimposing the packet signal on the prescribed line of a video signal by a packet inserting circuit 11b. Then, the patterns are detected for each decided data quantity with respect to the packet signal and a table converting processing into the numerical values of the filter characteristics which are registered in the table is successively executed, based on the detection result so that the filter processing is executed in the packet signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waveform shaping filter processing apparatus for filtering a serial packet signal before superimposing a serial packet signal such as a video net cue signal and a character multiplex signal on the video signal. About the method.

[0002]

2. Description of the Related Art As is well known, a superimposing device used for a net cue signal, a character multiplexed signal and the like processes an analog video signal. On the other hand, in the case of net cue or character multiplexed serial packet data, the superimposing device edits using a computer or a digital processing circuit. For this reason, the superimposing device generates net cue or character multiplexed serial packet data edited by a computer or the like using an analog rectangular wave pulse generator, applies an analog waveform shaping filter to the rectangular wave, and outputs a video signal. Is superimposed. However, this analog waveform shaping filter has a problem of group delay and the like, and it is difficult to design and adjust the filter.

In recent years, video signals have been digitized, and accordingly, it has become possible for superimposing apparatuses to execute digital signal processing. That is, the edited digital information is processed digitally by mounting the microprocessor in the superimposing device. The waveform shaping eliminates the group delay problem by performing FIR (Finite Impulse Response) digital filter processing, and high-performance filter processing can be realized by increasing the number of filter taps.

In the above-described superimposing apparatus, if the FIR filter operation is directly performed by the microprocessor, one field (16.7 m) is used in the net cue data.
During s), 735 words (10 bits per word) and character multiplexed data must be processed at a maximum of 2960 words.
Therefore, increasing the number of taps in order to improve the filter characteristics, even the latest high-performance microprocessor,
Processing within one field becomes difficult, a circuit using a dedicated filter IC (Integrated Circuit) or the like is required, and the size of the filter circuit increases according to the number of taps. In this case, the calculation accuracy also becomes a problem.

[0005]

As described above, in the conventional waveform shaping filter, the circuit scale is increased by increasing the number of taps in order to obtain good filter characteristics with digitization. In addition, there is a problem that the calculation accuracy is reduced.

SUMMARY OF THE INVENTION An object of the present invention is to provide a waveform shaping filter processing apparatus and method capable of greatly reducing the number of arithmetic processing operations when filtering a packet signal and realizing real-time processing.

[0007]

A waveform shaping filter processing device according to the present invention is a device for generating a packet signal having a specific pattern at the head of a packet, and superimposes the packet signal on a predetermined line of a video signal. When used in a pre-stage, a table in which numerical values of filter characteristics corresponding to all patterns that can be taken within a predetermined data amount in a packet signal are registered, and for a packet signal, Filter processing means for detecting the pattern and sequentially executing a table conversion process into numerical values of the filter characteristics registered in the table based on the detection result, thereby filtering the packet signal. It is.

According to this configuration, before the packet signal is superimposed on the predetermined line of the video signal, the numerical values of the filter characteristics corresponding to all possible patterns within the data amount determined in the packet signal Is registered in a table, and a pattern is detected for each packet data in a predetermined data amount. Based on the detection result, a table conversion process into a numerical value of the filter characteristic registered in the table is performed. By being sequentially executed, filter processing is performed.

As a result, since no arithmetic processing in the filter processing is performed on the packet signal, the number of times of processing can be greatly reduced, and real-time processing using a microprocessor can be easily constructed.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a block configuration of a net queue superimposing device to which an embodiment of the present invention is applied.

In FIG. 1, reference numeral 11 denotes a net queue superimposing device. This net queue superimposing device 11
Can be roughly classified into a serial / parallel converter 11a, a packet insertion circuit 11b, and a parallel / serial converter 11b.
c, a D / A (Digital / Analog) converter 11d, a packet generation circuit 11e, a LAN (Local Area Network) interface 11f, a parallel interface 11g, and a serial interface 11h.

In the net queue superimposing device 11,
The LAN interface unit 11f receives, via a terminal 11i, control information to be superimposed on a net queue signal having a specific pattern at the head of the packet, and supplies the control information to the packet generation circuit 11e via the parallel interface unit 11g. The packet generation circuit 11e configured as a waveform shaping filter processing device generates a serial packet of a net cue signal based on the input control information, and converts the serial packet into a digital video signal filtered using a filtering algorithm. Has been converted to. All of the above processing is performed by the microprocessor included in the packet generation circuit 11e.

On the other hand, a serial video signal supplied via a terminal 11j is converted from a serial video signal into a parallel video signal by a serial / parallel converter 11a.
In the serial / parallel converter 11a, when the switch section 11k switches to the 10B (Bit) 1C (Complementary) side, one bit of complementary data is added to the serial video signal every 10 bits.

The parallel video signal is supplied to a packet insertion circuit 11b, and a net cue signal generated from a packet generation circuit 11e is superimposed on a predetermined line. The video signal output from the packet insertion circuit 11b is supplied to a parallel / serial converter 11c and a D / A converter 11d. The parallel / serial converter 11c adds 1 bit of complementary data to the parallel video signal every 10 bits by switching the switch section 11l to the 10B1C side, converts the parallel video signal into a serial video signal, and outputs it via the terminal 11m. I do. The D / A converter 11d converts the supplied parallel video signal into an analog video signal, and outputs the analog video signal via the terminal 11n.

The character multiplexing device has almost the same configuration as that of the net queue superimposing device 11, and performs the same processing. In the net queue superimposing device 11, 3
In the character multiplexing apparatus, the 5-tap filter processing is performed with the 25-tap filter processing without a dedicated filter processing circuit. Here, the microprocessor is 4-7M
The one of about IPS is used.

Next, the packet configuration of the net cue signal generated by the packet generator 11e will be described with reference to FIGS. That is, as shown in FIG. 2, the net cue signal is a 2.86 MHz NRZI (Noise Reduction Zer) composed of 147-bit packets.
o Inverter) In the serial information signal, [0] level is the pedestal value of the video signal, and [1] level is 70% of the white level of the video signal. Expressing this as a 14.3 MHz sampling 10-bit composite video signal,
[0] level is 240 in decimal, [1] level is 632
Becomes Further, when this is represented by a rectangular wave, as shown in FIG. 3, there are five 240 [0] levels and five 632 [1] levels. The entire packet can be represented as 735 pieces of video signal information.

Before the packet of the net cue signal is superimposed on the video signal output from the serial / parallel converter 11a, the packet generation circuit 11e needs to perform a rectangular wave data waveform shaping filter process on the net cue signal. In addition, it is necessary to superimpose the shaped data on a predetermined line for each unit field. Further, since a packet has an index indicating signal continuity, it is necessary to update packet information for each unit field. In the case of a character multiplex signal, up to four lines of serial packet data similar to the net cue signal are superimposed in one field.

Next, a description will be given of a filtering process executed in the packet generation circuit 11e. That is, the packet generation circuit 11e performs filtering of the 735 data constituting the packet of the net cue signal by an FIR filter through arithmetic processing using a microprocessor. If the filter tap is set to 25 taps, As shown in FIG. 4, 18375 multiplications and additions are required. For 35 taps, 25
725 times.

Before performing the operation, the packet generation circuit 11e converts the serial packet data generated via the terminal 11p and the serial interface unit 11h into one.
Since it is necessary to instruct the parallel interface unit 11g to change the data to 0-bit parallel data, the corresponding processing is required. Further, the packet generation circuit 11
In e, if the arithmetic processing is performed by the microprocessor in real time, a microprocessor having a high arithmetic capability is required. Note that the parallel interface unit 11g is configured to directly input the parallel data input via the terminal 11o to the packet generation circuit 11e.

An example of a filter processing table conversion algorithm executed in the packet generation circuit 11e according to the embodiment of the present invention will be described with reference to FIGS.

That is, the packet data of the net queue generated by the packet generation circuit 11e can be represented by binary values of 0 and 1, so that the pattern can be held in bit units as data. For this reason, the packet generation circuit 11e can have, as a table, numerical values that can be obtained in units of bits in the packet data and that have been subjected to filter calculations in advance in a form corresponding to all patterns. For example, 3
When a 5-tap filter is configured, there are five tables in which filters for 8 bits of serial data are calculated.

Each table stores, within the range shown in FIG. 5, the result of filtering the video signal in association with all possible 8-bit patterns. Then, the packet generation circuit 11e converts the serial data of the packet into
Filtering can be performed by sequentially converting the table in units of 8 bits. When this algorithm is used, the entire packet can be executed by the table conversion of 735 times of the filter processing, so that the number of times of the processing can be greatly reduced as compared with the case of directly calculating.

When the number of taps is increased, the number of operations increases in the case of direct calculation, but in the case of table conversion, only the number of conversion bits needs to be increased. The number of processing does not change even if becomes larger. For example, when configuring a 45-tap filter, the table may be configured with 10-bit serial data as shown in FIG. Further, in the stage of creating the table, the accuracy of the filter coefficient can be obtained as much as possible, so that there is no problem in the calculation accuracy.

The above-mentioned table conversion process detects a pattern of the serial data of the packet, for example, every 8 bits, reads a filter processing result corresponding to the detected pattern from the table, and reads the filter processing result. Is to be sequentially converted to

Therefore, according to the above embodiment, before the packet data is superimposed on a predetermined line of the video signal in the packet generation circuit 11e, the packet data is divided into bit units corresponding to the number of taps of the filter in the packet data. Possible values of filter characteristics corresponding to all patterns are registered in a table, and the pattern is detected for each bit number corresponding to the number of taps in the packet data, and based on the detection result, The filter processing is performed by sequentially executing the table conversion processing into the numerical values of the filter characteristics registered in the table.

For this reason, since it is not necessary to perform arithmetic processing such as addition and multiplication in the filter processing on the packet data, the number of times of processing can be greatly reduced, and real-time processing using a microprocessor can be performed. Can be easily constructed.

Further, if the table conversion process in the above embodiment is used, the filtering process for packet data and the conversion from serial data to 10-bit parallel data can be performed simultaneously. In other words, the table-converted value can be superimposed as it is as a parallel video signal on a predetermined line of the video signal input to the packet insertion circuit 11b. Therefore, like the direct operation, the serial data is transferred to the parallel interface unit 11 before the operation processing.
g does not need to be converted to parallel data, and the processing load on the parallel generation circuit 11e is reduced accordingly.

Further, in the above-described embodiment, a net cue signal has been described as an example. However, if the above-mentioned table conversion processing is applied, even if the packet data is a character multiplexed signal or a data broadcast signal, It goes without saying that the same operation can be carried out.

Further, the packet generation circuit 11 e
Although the packet data is generated based on the control information supplied from the AN interface unit 11f side, the packet data may be generated by controlling the switching of the switch unit 11r. Further, the setting of the table according to the number of taps of the filter in the packet generation circuit 11e or the processing operation of the microprocessor is L
Control information supplied from the AN interface unit 11f side or switching control of the switch unit 11r may be performed.

It should be noted that the present invention is not necessarily limited to the above-described embodiment, and it goes without saying that various modifications can be made without departing from the spirit of the present invention.

[0031]

As described in detail above, according to the present invention,
It is possible to provide a waveform shaping filter processing apparatus and method that can greatly reduce the number of arithmetic processing times and perform real-time processing when performing filter processing on a packet signal.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a net cue superimposing device to which an embodiment of a waveform shaping filter processing device according to the present invention is applied;

FIG. 2 is a diagram showing an example of a packet configuration of a net queue signal according to the embodiment.

FIG. 3 shows a case where the net cue signal in the embodiment is 10
The figure represented by the composite video signal of bits.

FIG. 4 is a table showing the number of operations and the number of table conversions corresponding to the number of filter taps in the net cue signal according to the embodiment;

FIG. 5 is a diagram showing a calculation range of a table for a net cue signal according to the embodiment;

[Explanation of symbols]

 11: Net queue superimposing device, 11a: Serial / parallel converter 11a, 11b: Packet insertion circuit, 11c: Parallel / serial converter, 11d: D / A converter, 11e: Packet generation circuit, 11f: LAN interface unit, 11g: Parallel interface unit, 11h: Serial interface unit.

Claims (8)

[Claims] 1. An apparatus for generating a packet signal having a specific pattern at the head of a packet, wherein the apparatus is used in a stage before superimposing the packet signal on a predetermined line of a video signal, wherein the apparatus determines a packet signal in advance in the packet signal. A table in which numerical values of filter characteristics corresponding to all patterns that can be taken within the set data amount are registered. For the packet signal, the pattern is detected for each data amount, and based on the detection result, A waveform shaping filter processing apparatus, comprising: a filter processing unit that sequentially performs a table conversion process into a numerical value of a filter characteristic registered in the table, thereby performing a filtering process on the packet signal. 2. The table registers, in units of bits in the packet signal corresponding to the number of taps of a filter, numerical values of filter characteristics corresponding to all patterns, the filter processing unit comprising: Means for detecting a pattern for each of the number of bits of the packet signal, and performing a table conversion process on the entire packet based on the detection result into numerical values of the filter characteristics registered in the table. The waveform shaping filter processing device according to claim 1, wherein: 3. The waveform shaping filter processing device according to claim 1, wherein said packet signal is a net cue signal. 4. The waveform shaping filter processing device according to claim 1, wherein said packet signal is a character multiplexed signal. 5. The waveform shaping filter processing device according to claim 1, wherein said packet signal is a data broadcast signal. 6. The present invention is applied to an apparatus for generating a packet signal having a specific pattern at the head of a packet, and is determined in advance in the packet signal in a state before the packet signal is superimposed on a predetermined line of a video signal. In the case where a table for registering the numerical values of the filter characteristics corresponding to all the patterns that can be taken within the data amount provided is provided, for the packet signal, the pattern is detected for each data amount, and the detection result A waveform shaping filter processing method characterized in that a filter process is performed on the packet signal by sequentially executing a table conversion process into a numerical value of a filter characteristic registered in the table based on the above. 7. The table may be obtained in units of the number of bits of the packet signal corresponding to the number of taps of a filter.
The numerical values of the filter characteristics corresponding to all the patterns are registered. In this case, the pattern is detected for each of the bit numbers with respect to the packet signal, and the filter characteristics registered in the table are registered based on the detection result. 7. The waveform shaping filter processing method according to claim 6, wherein the table conversion processing into numerical values is performed over the entire packet. 8. The waveform shaping filter processing method according to claim 6, wherein the packet signal is one of a net cue signal, a character multiplex signal, and a data broadcast signal.