JPS6213178A - Sound information modulating device for muse system - Google Patents

Abstract

PURPOSE:To use a low speed and inexpensive differential modulation circuit by applying differential modulation to a PCM sound signal at first, converting it into a symbol string, applying time base compression to the symbol string, adding the control signal of the symbol form directly to the result and forming the sound information subjected to time base compression. CONSTITUTION:This invention relates to the fact that only the sound signal is subjected to a differential modulation and compression before independently of a control signal and the control signal of the direct symbol form is added to the compressed symbol string in the differential modulation system where modulation corresponding to preceding and succeeding signals is applied. An input sound signal is given to a BS-IIPCM encoder 11, where the signal is converted into a digital sound signal, given to a serial/parallel conversion circuit 12, where the result is converted into a parallel bit pair and subjected to differential modulation in a differential modulation circuit 13 and converted into a symbol (P, Q) string. The symbol is subjected to time base compression by a time base compression/control signal addition circuit 14 and a control signal is added, which is used for the modulation of an RF carrier in a 4-phase modulation circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Application of the Invention The present invention relates to an audio information modulation device for television broadcasting using the MTJ SF system.

BACKGROUND OF THE INVENTION Currently, the MIJSE system is being planned as one of the new television broadcasting services that utilize broadcasting satellites and the like.

In this MUSE method, an analog audio signal, which has conventionally been transmitted using a frequency division multiplexing method together with an image signal, is digitized and then transmitted using a time division multiplexing method together with an image signal.

That is, on the transmitting side, after digitizing the analog signal by pulse code modulation, the time axis is compressed to about 1/16, and this is transmitted in bursts within the vertical blanking period between each field, while the receiving side On the i! side, the time axis is expanded from the time axis compressed burst digital signal. ! After converting the audio signal back to a continuous audio signal, it is converted to an analog signal.

Furthermore, in the M TJ S R system, the image signal is transmitted as an FM modulated wave, and the time-axis compressed digital audio signal is transmitted as a carrier wave (RF
Carrier) is transmitted as a differential four-phase modulated signal. For this reason, a data pair obtained by differentially modulating a continuous 2-bit audio data pair is called a symbol, and the transmission format of the MTJ SF system is defined using this concept of a symbol.

In other words, the transmission format of the MTJSR method is
As shown in the figure, it is described by a line number and a transmission → j-numble number, each line corresponds to one horizontal scanning amount of the image signal, and each transmission sample consists of one symbol.

Between the first field of image information that starts from line 44 and ends at line 576, and the second field of image information that starts from line 605, passes through the maximum line 1125, and ends at the next 5th line. During the vertical blanking period that exists in , 37 lines of audio information are transmitted. Also, within the vertical blanking period existing between the second field of image information and the next first field l, 38
Audio information for each line is sent out. 480 transmission samples are allocated to one line of each audio information hn range.

Image information first. The second field consists of the image signal and associated control signals, and the audio information area consists of the audio signal and associated control signals.

The reason why the size of the audio information area is 37 lines and 38 lines is to synchronize the entire signal system including the video signal. Similarly, from the viewpoint of synchronization, the transmission format of each audio information area includes a leap field that appears once every 15 fields and 14 fields in between.
There are two types of non-leap fields that appear twice in a row.

If the transmission format is 1" with a non-leap field, the last line (
Only the 43rd and 60404th transmission mats are different, and all other lines are exactly the same.

That is, both non-leap fields and leap fields,
Each line except the last line is transmission 4 no.1 sample number 1
A guard signal period G1 from 18 to 18, an introduction symbol signal (RIS signal) period of transmission sample number 19, an audio signal period from transmission sample numbers 20 to 475, and a guard signal period G2 of transmission sample numbers 476 to 480. It consists of

During the guard signal period G1, symbols of the last transmission sample number 480 of the preceding line are continuously transmitted. However, in the first line of each burst (line 6 or 568), the last line of the preceding burst (line 43 or 604)
The symbols with the last transmitted sample number 480 are transmitted continuously.

During the guard signal period G2, the symbol of the last transmission sample number 475 of the audio signal on the line is continuously transmitted.

Furthermore, during the RTS signal period, the same symbol as the symbol of the last transmission sample number 475 of the audio signal on the preceding line is transmitted. However, on the first line (line 6 or 568) of each burst, the same symbol as the symbol of the final transmission ramble number 459 or 455 of the audio signal on the last line (line 43 or CO604) of the preceding burst is transmitted. be done.

For non-leap fields, the last line 43 or 604
The audio signal on the line ends with transmission sample number 459,
The R signal is transmitted during the period from transmission sample numbers 460 to 475. During the guard period G2, symbols greater than or equal to the symbol of the final transmission sample number 459 of the audio signal on the line are continuously transmitted.

In addition, in the case of Leapfield, the final line 43 or 6
The transmission of the audio signal on line 04 ends at sample number 455, and the R signal is sent out during the period from transmission sample numbers 456 to 475. During the guard signal period G2, the same symbol as the symbol of the last transmission sample number 455 of the audio signal of that line is continuously transmitted.

1- The symbol string of the R signal inserted into the final line is:
The subsequent feel lζ is a non-leap feeling].
Depending on the field, data corresponding to 2-16 consecutive 0's or binary 1-consecutive data is transmitted. As mentioned above, the leap field appears periodically at a rate of once every 15 fields, so within the R signal period of the 14th non-leap field,
Sixteen symbol strings corresponding to one continuous data are sent out, and in the R signal period of the other non-leap fields and single beam fields, symbol strings corresponding to zero continuous data are sent out.

The transmission formant described below is for a field frequency of 60/1.001 Hz.

When the field frequency is 601 T z , the number of R signals transmitted is 32 symbols in the non-leap field and 36 symbols in the leap field, and the other points are the same as in the case where the field frequency is 60 /1.001.

A configuration as shown in FIG. 12 has been proposed as a modulating device for audio information using the JukiMIJSR method.

The analog audio signal supplied to the input terminal IN is B5-
After being converted into a PCM signal by the 11" CM encoder 1, the time axis is compressed to approximately 1/16 by the time axis compression 2. The guard signal G is added to the time axis compressed audio PCM signal by the control signal addition circuit 3. , I'? The bit pair is differentially modulated in the differential modulation circuit 5 and then used for modulating the RF carrier in the 4-phase phase modulation circuit 6.The differential 4-phase phase modulated wave is sent to the antenna system from the output terminal 01JT. Supplied.

Problems to be Solved by the Invention Since the audio information modulation device described above is configured to differentially modulate audio information consisting of a time-base compressed audio signal and a related control signal, it is possible to perform differential modulation at high speed. There is a problem in that the differential modulation circuit becomes expensive.

Configuration of the Invention Means for Solving the Problems The audio signal modulation device of the invention differentially modulates a pulse code modulated audio signal to convert it into a symbol string before compressing the time axis, and converts this symbol string into a symbol string over time. By adding a direct symbol-type control signal to the axis-compressed audio information to create time-axis compressed audio information, a low-speed and inexpensive differential modulation circuit can be used.

That is, even in a differential modulation method in which modulation is performed in accordance with the context of a signal, the present invention first differentially modulates and compresses only the audio signal independently of the control signal, and the This was done based on the knowledge that it is possible to directly add a symbol-type control signal to a compressed symbol string using a simple circuit, thereby realizing a reduction in the cost of the modulation circuit.

Hereinafter, the operation of the present invention will be explained in detail together with examples.

Embodiment FIG. 1 is a block diagram showing the configuration of an MIJSR type audio information modulation circuit according to an embodiment of the present invention.

This audio information modulation circuit includes a B5-ll PCM decoder 11, a serial/parallel conversion circuit 12, and a differential modulation circuit 13.
, a time axis compression/control signal addition circuit 14, and a four-phase phase modulation circuit I5.

The analog audio signal supplied to the input terminal IN is BB5
-11Pc encoder 11 converts it into a digital audio signal. This digital audio signal is immediately converted into parallel bit pairs in the serial/parallel conversion circuit 12, then differentially modulated in the differential modulation circuit 13, and converted into a symbol (P, Q) sequence.

The symbol (P, Q) sequence is time-base compressed and added with a control signal in a time-base compression/control signal addition circuit 14, and is used for modulating an RF carrier in a four-phase phase modulation circuit. The RF carrier modulated with the symbol string is supplied to the antenna system from the output terminal OUT.

(]0) The differential modulation circuit 13, as shown in FIG.
It consists of an ulo 4 adder circuit and a delay circuit for one symbol.

Data bit pair Dn (r), , r)2 >
and the previous symbol 511-1 (P', Q')
A modulo 4 addition is performed for , and new symbols S, , (+), Q) are generated.

That is, data bit pair Dn (r')+, D
z).

The relationship between the previous symbol 5ll-+ (P'', Q') and the new symbol S. (P, Q) is as shown in Figure 3. However, the symbols are expressed in Gray code, and rOJ −(0,0),rlJ −(0,I)r2J
= (1, O), r3J = (1, 1).

After the symbol sequence II differentially modulated in this way is subjected to four-phase demodulation on the receiving side, as shown in FIG.
Using a differential demodulation circuit consisting of an odulo 4 subtraction circuit and a one-symbol delay circuit, the original data bit pair V)n (r)+ is recovered according to the algorithm shown in FIG.
, Dz).

FIG. 6 shows the time axis compression/control signal addition circuit 14 in FIG.
FIG. 2 is a block diagram showing the configuration of FIG.

This time-base compression/control signal addition circuit includes a serial/parallel conversion circuit 21. which is concerned with time-base compression for a P signal sequence in a symbol sequence. Launch circuit 22. P signal system consisting of RAM 23 and parallel/serial conversion circuit 24, and Q in symbol string
A parallel/parallel conversion circuit 31 involved in time-base compression of the signal sequence. Launch circuit 32. A Q signal system consisting of a RAM 33 and a parallel/serial conversion circuit 34, a timing control circuit 35 and an address generation circuit 36 common to both the P and Q signal systems, and gates and flip circuits configured for each of the P and Q signal systems. A flop group 37 is provided.

The P signal string in the symbol string is shifted in synchronization with the low-speed clock signal CKr supplied from the timing control circuit 35 in the serial/parallel conversion circuit 21, converted into an 8-bit parallel P signal string, and then launched. RA via circuit 22
It is temporarily written to M23. Similarly, the Q signal string in the symbol string is also shifted in synchronization with the low-speed clock signal CKL in the serial/parallel conversion circuit 3I and converted into an 8-bit parallel Q signal string.
It is converted into a signal string and written into the RAM 33 via the latch circuit 32. Writing to the RAMs 23 and 33 is performed continuously one word at a predetermined period.

During the vertical blanging period, between the writing of word m to the RAMs 23 and 33, the RAMs 23 and 3 are
3, high-speed reading in word units is performed at a cycle that is approximately 1/16 of the write cycle.

However, if writing and reading conflict, reading takes priority, and writing of one word is performed after waiting for the reading of one word to be completed.

In this way, the word P signal string read out from the RAM 23 is converted to the clock signal CKL supplied from the timing control circuit 35 in the parallel/serial conversion circuit 24.
It is shifted in synchronization with the high-speed clock signal CK)T, which is approximately 16 times faster than the clock signal CK), and becomes a serial p signal string whose time axis is compressed to about 1/16 (I3), and then the exclusive OR game 1-EX is generated. ] is supplied to one input terminal of the

Similarly, the 1-word Q signal string read from the RAM 33 is also shifted in synchronization with the high-speed clock signal CKH in the parallel/serial conversion circuit 34, and is converted into a serial q signal string whose time axis is compressed to 1/16. Then, the exclusive disjunction game 1-
It is supplied to one input terminal of EX2.

Note that the shift operation of the parallel/serial conversion circuits 24 and 34 by the high-speed clock signal CKH is performed during periods other than the audio signal transmission period (the control signal transmission period within each field and the audio information non-transmission period between each field). is a signal IN to the shift inhibit l supplied from the timing control circuit Pr35.
It is prohibited by H.

Exclusive OR game) EX from the timing control circuit 35
The control signal insertion signal A supplied to the other input terminal of EX1 and EX2 is always kept at a logic low level except during the sending period of the R signal consisting of 16 consecutive data pairs (1, 1). . Therefore, audio signals and control signals (Gl, G2.RI
If both p and q signals of S signal and data statement, 1 signal other than 1 (1, 1) are 11-, a low signal is sent, and if high, a high signal is sent, but exclusive OR game 1-EXI , P: is output from X2. That is, the R signal of the data pair (1, I) and the audio information of 1 are directly passed through the exclusive OR gate F,
Xl, I finished rEX2]゛Game-1・A1
It is supplied to one input terminal of A2.

From the timing control circuit 35 to A1-A1.

The preamble insertion signal B supplied to the other input terminal of A2 goes high only during the period from line 6 to line 43 and from line 568 to line 604, as shown in FIG. Ru. Therefore, the ant gate Al, A2
is the exclusive OR gate F”:XI, EX2 to 1
1 (The audio information consisting of the supplied audio signal and control signal is passed through as is.

Except for the audio information transmission period, the AI is used.

The signal applied to the other input terminal of A2 goes low and the crumble (preamble) of FIG. Ru.

This clamp level (preamble) is applied to image information by transmitting a phaseless modulated wave corresponding to the symbol (0, 0) at a frequency corresponding to the intermediate value between the highest and lowest gradations of the image signal. provides a clamp level and provides a preamble for audio information.

shift from the timing control circuit 35 to the parallel/serial conversion circuits 24 and 34 over the period of the guard signal G2 from the 476th transmission sample number to the 480th transmission sample number of each line]
・Inhibit 1] U signal (I N H) is supplied, and the shift of each parallel/series circuit is inhibited. Therefore, over the period of the guard signal G2, five symbols identical to the symbols of the final audio signal with transmission sample number 475 are continuously transmitted.

Even during the transmission period of the guard signal G1 and RIS signal from the 1st to 199th transmission sample number of the next line, the timing control circuit 35 continues to send the shift inhibit 1 signal (INII) to the parallel/serial conversion circuits 24 and 34. continues to be supplied and each parallel/series circuit shift is still inhibited.
h is done. Therefore, after a period between guard signal G1 and RIS signal transmission, the same symbol as the 480th symbol transmitted on the preceding line, that is, transmission sample number 4.
The symbol that is the same as the symbol of the final audio signal number 75 is 1
Nine pieces continue to be sent out in succession.

However, in the first line of each audio information field (line 6 or 568), the last transmitted sample number 480th symbol of the last line of the preceding field (line 43 or 604) (this is the 480th symbol of that last line, as described below) 19 symbols identical to the symbol of the last transmitted sample number 459 or 455 of the audio signal are continuously transmitted.

Next, a method for sending the R signal will be explained.

(r) When sending an R signal consisting of a series of data pairs (], ]).

In the field immediately before the leap field, when the transmission of the R signal consisting of 16 consecutive data pairs (1, l) is started, the shift inhibit 1 signal supplied from the timing control circuit 35 is controlled by the signal TNII to Shifting of serial conversion circuits 24 and 34 is prohibited. As a result, the symbol of the audio signal with the 459th transmission sample number (p4sq
-4459) continues to be supplied. In synchronization with this, the 8th
As shown in the waveform diagram in the figure, the R signal insertion signal A is alternated between high and low at the transmission sample period.

If the symbol (pasq + Q459) is (0,0) as shown in the top row of the table in FIG. 8, then the R signal insertion signal A at transmission sample number 460
By rising to high (1), the symbol (1,
1) is the exclusive OR gate EXI.

It is output from EX2, passes through AND gates Al and A2 and flip-flops FFI and FF2, and is sent to the receiving side as a symbol (p46°, q46°) with transmission sample number 460.

At the next transmission sample number 461, the R signal insertion signal A falls to low (0), causing the symbol (0
, 0) is IJ and other disjunction game) EX I.

F and X2, and is sent to the receiving side as a symbol (1) 4615Q4&l) of transmission sample number 461 via AND gates Al and A2 and flip-flops FFI and FF2.

At the next transmission sample number 462, the R signal insertion signal A rises to high level again, causing the symbol (1,
1> are exclusive OR gates F, X].

It is output from F and X2 and sent to the receiving side as a symbol (p462, qsb□) with transmission sample number 462.

In this way, as shown in the top row of the table in FIG. 8, symbols (0, 0) and (1, 1) are alternately transmitted to the receiving side, and the final transmission sample number 475 of the R signal transmission period is Now, return to the symbol (0,0) of transmission sample number 459 immediately before the R signal transmission period.

As is clear from the fourth row from the bottom and the bottom row of the table in Figure 5, symbol (0,0) and symbol (1,1)
With the alternation of the data, the data (], ]) are continuously reproduced on the receiving side.

If the symbol (pasq + q4!, 9) is (0,]) as shown in the second row of the table in FIG. p
4bo + q4bo ) is flipped to (10) and becomes (0,]) at the next symbol (pab+ , Q461 )
The final symbol (pn7s, Q47s) of the R signal insertion period is
The symbol immediately before the R signal insertion period (pasq + Q
Return to 4S9).

As is clear from the third and second rows from the bottom of the table in Figure 5, the symbol (0, 1) and the symbol (], 0)
Data (1, 1) is continuously reproduced on the receiving side as the data (1, 1) alternates.

If the symbol (psscr + qa5q) is (1,0) as shown in the third row of the table in FIG. 8, the next symbol will be (p
4. . , q46°) is inverted to (0, 1), and the next symbol (p461 + Q461) returns to (1, 0). The final symbol (p47S, Q47S) of the R signal insertion intercostal space is , the symbol immediately before the R signal insertion period (p4sq + q4S9
).

As is clear from the second and third rows from the bottom of the table in Figure 5, the symbol (1,0> and the symbol (0,1)
Data (1, 1) is continuously reproduced on the receiving side as the data (1, 1) alternates.

If the symbol (p459, qs5q) is (1, 1) as shown in the fourth row of the table in FIG.
．． . , q46°) is inverted to (0,0), and the next symbol (T3ah+r q461 ) returns to (1,1>), which is the symbol inversion that repeats, and the final symbol of the R signal insertion period (p47s + Qa, s ) is the symbol immediately before the R signal insertion period (pasq + Q459
).

As is clear from the bottom row and the fourth row from the bottom in the table of FIG.
With the alternation of >, data (1, 1) is continuously reproduced on the receiving side.

When the signal A supplied to the other input terminals of exclusive OR gates EXI and EX2 falls to low with the start of the guard period from the next transmission sample number 476, the final symbol of the R signal transmission period (p4751 44?S)
are sent out in succession as they are, and 19 more (T)495°Q47S) from transmission sample numbers 1 to 19 of the first line 6 or 568 of the next leap field are sent out in succession, and on the receiving side, , the last symbol of the preceding non-leap field audio signal (p459 + Q4
59) is preserved.

(II) 16 or 20 consecutive data pairs (0°0
) when sending an R signal consisting of

In this case, as mentioned above, transmission sample numbers 460th to 475th for non-leap fields, and transmission sample number 456 for leap fields.
From the 475th to the 475th, the timing control circuit 35 sends a shift prohibition signal ((N
H) and exclusive OR game) F, X],
Set the signal A supplied to EX2 low.

As a result, 16 identical symbols held in the parallel/serial conversion circuits 24 and 34 are successively transmitted in the non-leave field and 20 in the leap field. On the receiving side, as is clear from the first to fourth rows in the table of FIG. 5, consecutive data pairs (0, 0) are reproduced with the succession of arbitrary symbols. .

In this way, the insertion of an R signal that continuously sends out a predetermined number of symbols corresponding to data pairs (1, I) and (0, 0) is prohibited in the shift operation of the parallel/serial conversion circuit. ,
Exclusive OR gate EX.

This can be easily realized by installing EX2, alternating the signals supplied to the other input terminals of these exclusive OR gates for each symbol, or dropping the signal to low.

In the following, a configuration in which a control signal is added using an exclusive OR gate and an AND gate has been exemplified, but various equivalent modifications can be made.

For example, the final audio symbol held in a time-base compression parallel/serial conversion circuit is supplied to a flip-flop,
By alternately sending out the non-inverted output and the inverted output, it is also possible to send out the R signal immediately before the leap field.

Effects of the Invention As explained in detail above, MIJ S related to the present invention
An IF audio modulation device performs differential modulation on a pulse code modulated audio signal before time-base compression, and adds a control signal symbol to the time-base compressed symbols after differential modulation. Since the configuration creates time-base compressed audio information, the effect is that a low-speed and inexpensive differential modulation circuit can be used for audio signals.

Furthermore, since the audio information modulation device of the present invention is configured to directly add a symbol-format control signal to a compressed audio symbol, an effect is achieved in that a differential modulation circuit for control information is not required.

[Brief explanation of the drawing]

FIG. 1 is a functional block diagram showing the configuration of an M tJ SE type audio modulation device according to an embodiment of the present invention. Fig. 2 is a functional block diagram showing the configuration of the differential modulation circuit shown in Fig. 1, Fig. 3 is a conceptual diagram for explaining the operation of the differential modulation circuit shown in Fig. 2, and Fig. 4 shows the difference on the receiving side. FIG. 2 is a functional block diagram showing the configuration of a dynamic demodulation circuit. FIG. 5 is a conceptual diagram for explaining the operation of the differential demodulation circuit of FIG. Figures 7 and 8 are signal timing diagrams for explaining the operation of the circuit in Figure 6, Figures 9 to 11 are transmission format diagrams of the MIJSE system, and Figure 12 is the configuration of a conventional audio modulation device. 11. BS-If encoder, 12. Serial/parallel conversion circuit, 13. Differential modulation circuit, 14. Time base compression/control signal addition circuit, 15. 4-phase. Phase modulation circuit, 21
．． 31...Serial/parallel conversion circuit, 22.32...Launch circuit, 23.33...RAM, 34...Parallel/serial conversion circuit, 35...Timing control circuit, 36...Address generation circuit. 37...Gate and flip-flop circuits.

Claims (1)

[Claims] A modulation means that performs pulse code modulation on an analog audio signal and then performs differential modulation to convert it into an audio symbol string; a time axis compression means that compresses the audio symbol string in the time axis; and control information adding means for adding symbols of a guard signal, an introduction symbol signal, and an R signal to the audio symbol string, and the control information adding means adds the symbols of the guard signal, the introduction symbol signal, and the R signal to the audio symbol string, and the control information adding means transmits the audio signal after the end of the audio signal transmission period until the start of the next transmission period. The final audio symbol at the end of the period is held in the time axis compression means, and during the sending period of the R signal in the field immediately before the leap field, the final audio symbol held in the time axis compression means is alternately held at the symbol sending period. 1. A MUSE type audio information modulating device, comprising a control means for continuously transmitting the final audio symbol at a symbol transmission period during all other control information transmission periods.