JPH0574117A - Converting device of timing signal of rotary head type recording-reproducing apparatus - Google Patents

Abstract

PURPOSE:To conduct a writing control and a reading control discretely for a recording time area and a reproducing time area in which a time code is stored, for the purpose of preventing the imperfection of recording and reproduction of the time code which is caused by a slippage between a head rotation period of R-DAT and an external timing period. CONSTITUTION:A semiconductor memory 2 having first and second memory areas is provided and a timing circuit 1 which selects them alternately for writing data and for reading these written data is provided. Thereby a converting device of a timing signal which dispenses with an interrupt processing of a microprocessor 4 converting the timing signal being synchronous with a rotary head and the timing signal being asynchronous therewith is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a rotary head type recording / reproducing apparatus with a time code asynchronous with the rotation of the rotary head (for example, a time code in the longitudinal direction of the tape) and a fixed head for recording / reproducing the time code. Without being concerned, the present invention relates to a timing signal conversion device for enabling recording and reproduction by a rotary head.

[0002]

2. Description of the Related Art In a rotary head type recording / reproducing apparatus, it is sometimes necessary to record / reproduce a time code which is asynchronous with the rotation of the rotary head. For example, in a rotary head type digital audio tape recorder (R-DAT), a video tape recorder (VT) for recording a video signal.
R) tape longitudinal direction time code (LTC: Longitud
It will be necessary to record the (inal Time Code) and make it convenient for editing. At this time, the recording / reproducing system follows the timing signal synchronized with the rotary head, and the input / output signal system uses the LT signal.
It becomes necessary to follow a timing signal that is asynchronous to the rotary head such as C.

In such a case, there is a method of recording a time code (LTC) in the longitudinal direction of the tape, a control signal for controlling the tape running, and the like by providing a recording track separately from the oblique recording track by the rotary head. However, in that method, it is necessary to provide a fixed head for recording in the tape longitudinal direction in addition to the rotary head. Therefore, the applicant of the present invention has disclosed a technique of converting a time code into a sub-code area of an oblique recording format of R-DAT and recording the converted time code so that a longitudinal recording track by a fixed head is not provided. -Proposed to 29391.

In the technique proposed in Japanese Patent Laid-Open No. 63-29391, when a 30 Hz time code corresponding to a head rotation of a rotary head type VTR, for example, 30 rpm, is used,
It is possible to record and reproduce a 30Hz time code on an R-DAT with a head rotation speed of 100/3 rotations / second. Therefore, a time code reading circuit, a time code generating circuit, a counter for counting bit numbers, and a latch circuit for latching this value are provided, and a carry pulse for the counter is generated for each predetermined value. The carry pulse is supplied as the reference synchronization signal.

However, in the actual hardware configuration, even when the technique described in JP-A-63-29391 is used, it is necessary to cooperate with other related operations. It is rational to provide a microprocessor (MPU) for timing control of the time code generation circuit or to configure the MPU to perform time code reading and time code generation.

In such a case, for example, as in the work time allocation example shown in FIG. 5, during the operation of the MPU, the operation of the MPU by the timing signal synchronized with the rotary head and the operation by the timing signal asynchronous with the rotary head collide. It happens to fit. Therefore, it is necessary to interrupt one work and perform the other work, or to create a section that does not accept the interrupt and perform a lump work. Due to such processing, the timings of one side may be misaligned because the time may not be consistent,
There is a problem that part of the work is aborted or carried over to the next cycle. There is a problem that it is not easy to create an MPU program that involves interrupt processing, including the solution of these problems.

[0007]

SUMMARY OF THE INVENTION In the present invention, in the rotary head type recording / reproducing apparatus, the problems described in the prior art are solved and the interruption processing of the microprocessor for controlling the time code reading and the time code generation. It is an object of the present invention to obtain a timing signal conversion device capable of converting a timing signal synchronized with the rotary head and a timing signal asynchronous with the rotary head without the above.

[0008]

According to the present invention, there is provided a rotary head type recording / reproducing apparatus having a semiconductor memory having first and second memory areas, a timing signal synchronized with rotation of the rotary head, and a rotary head. A first memory area and a second memory area of the semiconductor memory in response to a timing signal asynchronous with the rotation of (eg, aligned with a longitudinal time code).
And a timing circuit for generating a memory area selection signal for alternately writing and reading the memory area of
At the time of recording information by the recording / reproducing apparatus, a time code is written in the semiconductor memory in accordance with an external timing signal asynchronous with the rotary head, and the written time code is stored in the rotation cycle of the rotary head (approximately). Read at a timing delayed by one cycle and record on the diagonal recording track with the rotary head (as a rotation cycle time code),
When information is reproduced by the recording / reproducing apparatus, the time code reproduced from the recording tape is stored in the semiconductor memory at a timing synchronized with (the rotation of) the rotary head (actually, converted into a timing of one cycle ahead). A rotary head type recording / reproducing apparatus which writes and reads the written reproduction time code at a timing asynchronous with the rotation of the rotary head (for example, in accordance with the time code in the longitudinal direction) and outputs it as tape position information. The timing signal converter of FIG.

[0009]

According to the present invention, a semiconductor memory having first and second memory areas is used, and after writing to the first memory area, the first memory area is read during writing to the second memory area. In this way, it is configured to repeat alternately. If data is read in the next cycle (a delay of approximately one cycle) after writing in this way, correct data can be read even if the memory write timing and the memory read timing are asynchronous.

If memory writing is performed at a timing synchronized with the rotation of the rotary head and reading is performed at a timing asynchronous with the rotary head, the rotary head reproduces the signal recorded on the oblique recording track, and the rotary head is read. Data such as a time code can be output at asynchronous timing. However, since the data is read out with a delay of about one cycle as compared with the time of writing to the semiconductor memory, the read time code data is replaced by the time code data of about one cycle ahead in the calculation to restore correct data.

As described above, according to the timing signal synchronized with the rotary head and the timing signal asynchronous with the rotary head in the input / output data system, the selection signal for selecting the write and read memory areas of the semiconductor memory is provided. A timing circuit is provided to generate, thereby eliminating the need for the microprocessor to handle interrupts.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described with reference to the block diagrams shown in FIGS. For the sake of clarity, the recording is shown in FIG. 1 and the reproduction is shown in FIG. 2, but the actual hardware is the timing circuit 1 and the semiconductor memory.
2 , a reader / generator 3, and a processor 4 are provided so that they can operate both during recording and during reproduction by selecting an operation mode. For example, the reader / generator 3 can program a microprocessor to operate as both a reader and a generator. Of course, it is also possible to configure each by a logic circuit and switch and use them.

As shown in FIG. 1, the structure at the time of recording is the first
The semiconductor memory 2 having the memory area and the second memory area, and the timing circuit 1 which alternately repeats one of the memory areas and writes the other so as to generate the memory area selection signal. The left side of FIG. 1 is a recording / reproducing system, which operates according to a timing signal synchronized with the rotation of a rotary head (not shown), and the right side of FIG. 1 operates according to a timing signal asynchronous with the externally input rotary head.

First, an external input time code (asynchronous to the rotary head) is input to the reader / generator 3 .
The reader / generator 3 is a reading circuit (READ
ER) 3A, timing circuit (TC SYNC) read from external input time code
1 and sends the time code data read by the reading circuit 3A to the semiconductor memory 2 at the timing of the TC SYNC.

At this time, which of the two memory areas of the semiconductor memory 2 is used for writing, which is for reading, and what is the read timing depends on the selection signal generated from the timing circuit 1 . The timing circuit 1 is a timing signal (ST
The memory area selection signal is generated from the timing signal (TC SYNC) asynchronous with ART). At the time of recording, the simple timing circuit shown as 1A in FIG. 1 can be used.

From the timing circuit 1 , the reading circuit 3
A memory write area selection signal (RDR W SEL) for writing the external input time code data asynchronous to the rotation read by A at the timing of the external input data, and the external input time written in the semiconductor memory 2. A memory area selection / readout timing designation signal (PRC R SEL) for the processor 4 to read out the code data at a timing synchronized with the rotary head at the next cycle (delayed by about 1 cycle) is generated. The read time code data is converted into a tape recording time code (synchronized with the rotary head) by converting the data format into a form suitable for tape recording by the processor 4 (for example, parallel data to serial data), and is recorded on an oblique recording track. Record with a rotating head. In the case of R-DAT, it is recorded in the subcode area. Here, the processor 4 is usually a microprocessor (MPU) and is synchronized with the control for the rotary head and the tape running. Note that the delay of the absolute value of the time code due to the reading with a delay of approximately one cycle described above has regularity as will be described later, and therefore can be corrected by calculation.

Next, as shown in FIG. 2, the structure at the time of reproduction is a semiconductor memory 2 having a first memory area and a second memory area, one of which is read and the other is written. 2 and a timing circuit 1 for generating a selection signal which is repeatedly selected alternately. The left side of FIG. 2 operates in accordance with a timing signal synchronized with the rotation of a rotary head (not shown) in a recording / reproducing system, and the right side of FIG. Operates according to a timing signal asynchronous to the rotary head,
The same as when recording. During reproduction, the processor 4 converts the reproduction time code data (synchronized with the rotary head) read from the diagonal recording track by the rotary head into a data format suitable for memory writing (for example, serial data into parallel data). 4 operates to write to the semiconductor memory 2 at a timing synchronized with the rotary head.

At this time, which of the two memory areas of the semiconductor memory 2 is to be used for writing and the reading timing is determined by the selection signal generated from the timing circuit 1 as in the case of recording. The timing circuit 1 generates the memory area selection signal from the timing signal (START) synchronized with the rotary head and the asynchronous timing signal (TC SYNC) in the same manner as during recording, but during reproduction, for example, It is based on the timing circuit shown as 1B in FIG.

From the timing circuit 1 , a memory write area selection signal (PRC W SEL) for writing the time code data synchronized with the rotary head to be written by the processor 4 into the memory at the timing synchronized with the rotary head. )
And the written data in the next cycle (delayed by about 1 cycle),
A memory read area selection / read timing designation signal (GEN R SEL) to be read by the time code generation circuit 3B of the reader / generator 3 is supplied to the rotary head at a timing of an asynchronous external time code.

Then, the time code data read by the time code generation circuit 3B is output to the rotary head at the timing of the asynchronous external time code. What should be noted here is that since the semiconductor memory 2 reads out with a delay of about 1 cycle, the tape position information will be delayed by about 1 cycle as it is. Therefore, processor 4
At the time of writing in the memory, the reproduced time code is calculated, and the signal data is recalculated to a correct time code value approximately one cycle ahead and the signal data is written in the semiconductor memory 2 . Details will be described later.

Next, this embodiment will be described with reference to a timing chart of an operation example. First, at the time of recording, the external time code (for example, LTC) input to the reading circuit (READER) 3A is synchronized with the rotary head.
A timing chart is shown in FIG. 3 for the case where the time code data at the rise of the START signal is desired to be known. In the example of FIG. 3, at the end of the sync signal portion of the READER input LTC, RE
External input time code (LTC) synchronization signal (TC SYNC) and time code values T ₁ , T ₂ , T ₃ as ADER output
T _i to (i is a positive integer) are output, and the memory write area selection signal (RDR W SEL) is output according to the TC SYNC, and T ₁ , T ₂ , T _{3 is} promptly output to the semiconductor memory 2. ~ T _i ~ is written. Here, the timing signal synchronized with the rotary head, for example, the START signal of 100 / 3Hz is the timing circuit.
When input to 1 , latch the inverted signal of the memory write area selection signal (RDR W SEL) at the rising edge of the START signal,
Generate the memory read area select signal (PRC R SEL).
That is, of the first and second memory areas of the semiconductor memory 2 , the memory area which is not being written is read by the processor 4 at the timing synchronized with the START signal. Therefore, the rising edge of the START signal is measured at the observation point F ₁ ,
Contents of time code data T ₁ , T ₂ , T _{3 to} T _i read as F ₂ , F _{3 to} F _i
Comparing (tape recording time code REC TC) with the original READER output, the number of T _i increases by one. As described above, it is inevitable that the time code is shifted by one, but since the pattern of the time code data is usually known, the time code value can be corrected by a simple calculation. This correction calculation may be performed by the processor 4 before recording on the tape, or may be performed on the reproduction output data when there is no restriction on the tape recording format.

Next, an example of a timing chart at the time of reproduction
As shown in FIG. Time code data read by the rotary head
Data T₁, T₂, T₃~ Are specified data format changes
After changing, the START signal synchronized with the rotation of the rotary head
Memory write area selection signal generated in response to rising edge
According to (PRC W SEL), semiconductor memoryTwoWritten in
It Here, the synchronization signal (T) of the external time code (LTC)
Memory write area select signal (PRC W
 Memory read obtained by latching the inverted signal of (SEL)
The memory area type specified by the area selection signal (GEN R SEL)
Read the imcode data. At this time, read
Contents of time code data T₁, T ₂, T₃~ T
_iIs the observation point F at the rising edge of the START signal₁,
F₂, F₃~ F _iData contents when writing to memory as
When compared with (playback time code PB TC)
Point F_iIs the next T_iSet to write values to memory
You know what you need to do. This calculation is T_iGranting of
It is normal for the playback serial data to be
When converting to parallel data, the time code during playback is
It can be easily performed by the processor 4 from the read value.

In the above embodiment, the timing circuit 1 is newly provided, the semiconductor memory 2 is provided with the two first and second memory areas, and the processor 4 needs to perform the time code data replacement calculation. But
The effect that the interrupt processing need not be performed in response to two synchronous signals of, for example, 100/3 Hz synchronized with the rotary head and 30 Hz asynchronous with the rotary head is significant.

[0024]

According to the present invention, a rotary head type recording / reproducing apparatus has a semiconductor memory having first and second memory areas, and writing is alternately performed and reading of the written data is performed. By providing a timing circuit for selection, the microprocessor interrupt processing is performed in order to convert the timing signal synchronized with the rotary head controlling the recording / reproducing system and the timing signal asynchronous with the rotary head in the input / output data system. A timing signal conversion device that eliminates the need for

This solves the difficulty of creating an interrupt program for avoiding the inconvenience that occurs when two timing signals, synchronous and asynchronous, collide with the rotary head during the working process of the microprocessor, and at the same time, the fixed head recording track. This facilitates the production of a recording / reproducing apparatus capable of recording an asynchronous timing code on the rotary head without providing a rotary head.

[Brief description of drawings]

FIG. 1 is a block diagram during recording according to an embodiment of the present invention.

FIG. 2 is a block diagram during reproduction according to the embodiment of the present invention.

FIG. 3 is a timing chart as an example of recording.

FIG. 4 is a timing chart as an example during reproduction.

FIG. 5 is an illustration of an example of MPU work time allocation. FIG. 1 Timing circuit 2 Semiconductor memory 3 Reader / generator 3A Read circuit 3B Time code generation circuit 4 Processor

Claims (1)

[Claims] 1. A rotary head type recording / reproducing apparatus having a semiconductor memory having first and second memory areas, wherein a semiconductor memory having a first memory area and a second memory area is provided. The semiconductor memory has a timing circuit for generating a memory area selection signal for alternately writing and reading the first memory area and the second memory area, and is asynchronous with the rotary head during the recording. Writing a time code to the semiconductor memory according to an external timing signal of the above, reading the written time code at a timing of rotation synchronization of the rotary head, and recording on the diagonal recording track by the rotary head, At the time of reproduction, the time code reproduced from the recording tape is stored in the semiconductor memory at a timing synchronized with the rotary head. The timing signal conversion device for a rotary head type recording / reproducing apparatus, wherein the written reproduction time code is read at a timing asynchronous with the rotation of the rotary head and is output as tape position information. ..