JPH0412545B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a reading speed control device for an information reading device, and more particularly to a reading speed control device for controlling the reading speed of recorded information on a recording disk on which video information is recorded. In a video disc on which video information is recorded, recesses (or protrusions) called pits are provided on the disc surface to form concentric or spiral tracks, and the length and spacing of these pits are Information is recorded by. Information is read from the video disk by using, for example, light as a reading means and demodulating reflected or transmitted light from the recording surface that is modulated depending on the presence or absence of pits on the disk.
Such an information recording disk reading device is provided with a tracking servo device that controls the rotation of a tracking mirror so that the irradiated light always accurately tracks the information track on the disk. There are the following three types of reading operations of this information reading device, each having a different reading speed. That is, a fast operation of reading video information every f fields from a recording disk in which video information of f fields (f is a natural number) is recorded on one recording track, and a step of sequentially reading each frame consisting of two fields. This is a stay operation in which the same frame is read repeatedly. These two operations, the fast operation, the step operation, and the stay operation, are performed by controlling the jump operation of the irradiation light so that the irradiation light jumps the recording track at regular intervals. That is, when the pits are provided on the recording disk to form a spiral track, the fast operation and the stay operation are performed by the jump operation of the irradiated light, and the pits form concentric tracks on the recording disk. In such a case, the fast operation and step operation are performed by the jump operation of the irradiated light. A method of controlling the jump operation of the irradiation light is, for example, by opening the tracking servo loop and rapidly rotating the tracking mirror in order to cause the irradiation light to depart from the recording track that the irradiation light was tracking at the same time as the tracking servo loop is opened. ,
Next, a method is adopted in which irradiation light is introduced to the recording track to be tracked to close the servo loop again. The information reading speed is determined by appropriately combining the fast operation, step operation, and stay operation. Conventional reading speed control devices that control this information reading speed are configured to use pulses with different pulse widths depending on the designated reading speed as a speed command signal to specify the information reading speed to a desired speed. Therefore, the number of signal lines of the transmission line for speed command signals can be reduced in consideration of remote control and the like. However, since the reading speed command must be transmitted while at least one field's worth of information is being read, the maximum pulse width of the pulse as the speed command signal is longer than the maximum pulse width required to read one field's worth of information. It will be limited by time. On the other hand, the minimum pulse width of the pulse as the speed command signal is limited by the response speed of the circuit receiving the pulse. Therefore, with conventional reading speed control devices, it is difficult to perform multi-step speed control, and information is read at a reading speed that corresponds to each pulse width of the pulse as a speed command signal. This method has the disadvantage that a plurality of control circuits are required to control the reading operation, making the configuration complicated. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a reading speed control device for an information reading device that is capable of performing multi-stage speed control and has a simple configuration. The reading speed control device for an information reading device according to the present invention corresponds to a specified reading speed with three types of commands: a step command for instructing a step operation, a first command for instructing a fast operation, and a stay command for instructing a stay operation. The apparatus includes a command generating means that sequentially generates commands as an alternative, and is configured to control the movement of the reading pickup on the recording disk in accordance with the generated commands. Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. In the figure, 1 is a remote control device as a command generation means. In remote control device 1, connect the volume between the power supply and ground.
The resistor of V _R and the resistor R are connected in series.
The slider of the volume V _R is connected to a series connection point between the resistor of the volume V _R and the resistor R. The position of the slider of the volume _VR on the resistor is set by the user according to the desired reading speed,
A voltage corresponding to the reading speed is derived at the series connection point between the resistor of the volume V _R and the resistor R, and the control circuit 2
supplied to The control circuit 2 includes an AD converter that converts a voltage according to the reading speed into coded digital data of a predetermined number of bits, a processor,
ROM (Read Only Memory), RAM (Random
It consists of a microcomputer that processes the output data of the AD converter and issues various commands. In the microcomputer in this control circuit 2, data processing is performed and various commands are issued as described below by a processor that operates according to a program stored in advance in a ROM. That is, first, initial values are set in registers, stack pointers, etc. inside the processor (R1 in FIG. 2). Next, the data output from the AD converter and indicating the speed commanded by the user is loaded into a register inside the processor.
It is temporarily recorded in a predetermined memory location in RAM (R in the same figure).
2). Next, a plurality of pieces of data previously stored in a predetermined storage area in the ROM designated by the storage contents at a predetermined storage location in this RAM are read out (R3 in the same figure). The data read from this ROM indicates the number and order of three types of operations: stay operation, step operation, and fast operation, to be performed according to the specified reading speed as shown in Tables 1 to 4. . Tables 1 and 2 show what the data supports when the specified reading speed is faster than the normal speed, and Tables 3 and 4 show that the specified reading speed is lower than the normal speed. The content of the data instruction in the case of is shown. still,
In Tables 1 to 4, when one frame containing information for one screen is formed by two fields, information for N fields is recorded on one recording track on the recording medium. The contents of support in the case of the following are shown. Next, the data read from the ROM is temporarily stored in a predetermined area of the RAM (R4 in the same figure). after that,
The trigger signal output from the speed control device 3 is continuously detected (R5 in the figure). When the trigger signal is detected, three pulses with different pulse widths corresponding to the stay operation command, step operation command, and fast operation command are generated according to the command contents of the data temporarily stored in a predetermined area of the RAM. Each time a trigger signal is output from the speed control device 3 one pulse at a time, it is sent to the transmission line 4 consisting of a single signal line (R6 in the figure). After that, the data output from the AD converter is loaded into the register inside the processor, and then stored in the RAM.
is temporarily stored in a predetermined storage location (R2 in the same figure). The pulses sent out to the transmission line 4 are supplied to the speed control device 3. In the speed control device 3, the pulse is supplied to a pulse width discrimination circuit 5. The pulse width discrimination circuit 5 discriminates the pulse width based on the count value of a counter that is counted up by a pulse generated at a predetermined repetition frequency only when a supplied pulse is present, and corresponds to the pulse width. It is configured to output a stale signal, a step signal, and a first signal. The stay signal and step signal output from the pulse width discrimination circuit 5 are supplied to a state control circuit 6, and the first signal is supplied to a first jump operation control circuit 8 in a jump operation control device 7. The state control circuit 6 is supplied with a trigger signal output from the trigger generation circuit 9 in synchronization with the start of reading information in the field. The state control circuit 6 also receives a code detection signal indicating whether or not there is a code F at the beginning of the field being read, indicating that it is the first field of one screen, and a direction instruction signal indicating the reading direction. Supplied. State control circuit 6
The reverse jump operation control circuit 1 in the jump operation control device 7 uses these stay signals, step signals, code detection signals, and direction signals.
0, the static jump operation control circuit 11 and the non-jump operation control circuit 12 are configured to supply a pulse synchronized with a trigger signal. That is, for example, when pits are provided on a recording disk to form a spiral track, the state control circuit 6 will control the direction control circuit 6 to move in the opposite direction if the direction instruction signal indicates the opposite direction when the step signal is supplied. A pulse is supplied to the jump operation control circuit 10 to read out the next field (FIG. 3, S1). Thereafter, if the stay signal is supplied, the state control circuit 6 performs a backward jump operation twice every time a trigger signal is supplied, if the code detection signal was not output during the first field reading. Control circuit 1
0 so that the fields two and three fields after the first field are read out, and if the code detection signal is output, a pulse is supplied to the reverse jump operation control circuit 10. The pulse is supplied twice so that the field two fields after the first field is read out (S2 and S3 in the same figure). Then, when the code detection signal is output again, the state control circuit 6
supplies a pulse to the standstill jump operation control circuit 11 so that only the same field is read (S4 in the figure). In the household described above, the state control circuit 6 operates so that the state of the speed control device 3 returns to the state S1 when the step signal is supplied. Next, if the direction indication signal indicates the positive direction when the step signal is supplied to the state control circuit 6, the state control circuit 6 sends the no-jump operation control circuit 12
A pulse is applied to cause the field following the first field to be read. (Figure S
5). Thereafter, when the stay signal is supplied, the state control circuit 6 supplies a pulse to the no-jump operation control circuit 12 every time a trigger signal is supplied until the code detection signal is output, and then reads out the next field. (S)
6) A pulse is supplied to the static jump operation control circuit 11 so that only the same field is read (S4 in the figure). In the above process,
When the step signal is again supplied to the state control circuit 6, the state control circuit 6 operates so that the state of the speed control device 3 returns to the state S1. On the other hand, the first signal is output from the pulse width discrimination circuit 5 and the first signal is output from the first jump operation control circuit 8.
If the direction indication signal indicates the forward direction when the direction indication signal is supplied, a jump operation is performed one track ahead, and if the direction indication signal indicates the reverse direction, a jump operation is performed two tracks later. . In the above embodiment, the stay operation command,
It is assumed that the transmission of each of the step operation command and the first operation command is performed by three types of pulses having pulse widths corresponding to each command, and one of the three operation commands is transmitted by the trigger signal. The three types of operation commands may be transmitted by two types of pulses, such that the pulses are not generated immediately after the pulses are generated. In addition, in the above embodiment, the operation command and the trigger signal are transmitted and received through two signal lines, but the output stage of the circuit that outputs the operation command and the trigger signal respectively has a high level output and a low level output. It is conceivable to use a three-state impossible circuit that can provide an invalid output in addition to an output, so that operation commands and trigger signals can be sent and received through a single signal line. As detailed above, the reading speed control device for an information reading device according to the present invention is configured to control the reading operation by selectively and sequentially generating three types of operation commands corresponding to a specified reading speed. Because there are 3
Speed control is performed by discriminating between different types of pulse widths and performing reading operations corresponding to each pulse width, making it possible to perform multi-stage speed control with a simple configuration. Therefore, the reading speed control device according to the present invention is suitable for use not only in optical information reading devices but also in any information reading device such as a capacitive information reading device.

【table】

【table】

Claims (1)

[Claims] 1 A reading speed control device for an information reading device that reads video information from a recording disk on which video information for f (f is a natural number) fields is recorded on a recording track for one revolution, and each frame consisting of two fields. There are three types of commands: a step command that commands an operation to read sequentially at least every f field, a fast command that commands an operation to read sequentially at least every f field, and a stay command that commands an operation to read the same frame repeatedly. A control means for controlling the moving operation of the reading pick-up on the recording disk in accordance with the generated commands. A reading speed control device for an information reading device, characterized in that: