JP3080704B2 - Magnetic playback device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to magnetic reproduction for setting data based on a clock edge, a data edge, and a time interval from the data edge to the next clock edge, and outputting the data as a reproduction signal. The present invention relates to an improvement of a magnetic reproducing apparatus having means.

[0002]

2. Description of the Related Art Conventionally, magnetic heads are used to write or read out film information such as film sensitivity and photographing information such as the date of photographing or the like from a magnetic storage unit provided in the film as necessary. An enabled camera is proposed in U.S. Pat. No. 4,864,332.

Further, a method of magnetic storage by a self-clocking method has been proposed in US Pat. No. 4,912,467, and a reproducing method has been proposed in US Pat. No. 4,876,697.

[0004]

However, in the above-described conventional example, the density of the magnetic layer for forming the magnetic storage portion must be reduced so as not to impair the transparency of the film. S / N was not large.

Further, since the film feeding of the camera originally did not consider the magnetic reproduction, the feeding speed fluctuates greatly depending on the state of the power supply and the load of the film feeding. The output of the signal was even smaller.

[0006] Also, noise of the motor and the like also causes S / S of the reproduced signal.
N was greatly affected.

As described above, a clock edge or a data edge may be lost during information reproduction.
Since a series of information to be represented by bits is missing one bit, an erroneous reproduction signal may be output.

The present invention has been made in view of the circumstances described above,
It is an object of the present invention to provide a magnetic reproducing apparatus that can output an accurate reproduction signal corresponding to the recorded information even if there is a reading error of the recorded information.

[0009]

Means for Solving the Problems To achieve the above object,
For example, the present invention relates to a method for storing a cell in a magnetic storage unit provided in a film.
Magnetic head for reading information recorded by
And a data edge read by the magnetic head.
Data edge detecting means for detecting edge, and the magnetic head
To detect the clock edge read by
Edge detecting means, detected clock edge and data
From the data edge to the next clock edge.
The data is set based on the time interval at
Reproducing apparatus provided with magnetic reproducing means for outputting as a signal
A discriminating means for discriminating a data edge detection error by said data edge detecting means in said magnetic reproducing means, and a data edge detection error by said discriminating means.
Is detected , a data edge detection error occurs
That it was provided with information setting means for setting information indicating
It is a feature .

In the present invention, the discriminating means discriminates the detection error of the data edge when the next clock edge comes again where the data edge should come after the clock edge. error - is if was made to set the information indicating that the detection error of the data edge occurs, de by parity checks that are performed after - and enables the data of the restoration.

[0011]

FIG. 1 is a schematic internal configuration diagram of a camera according to a first embodiment of the present invention, and FIG. 2 is a circuit block diagram of the camera.

In these figures, reference numeral 1 denotes a performance P of a film F having a magnetic layer applied to a base side.
1, a feed photoreflector for detecting a signal P2 and outputting a signal when the film F is fed at a constant distance, and a film feed motor 2 disposed in a film take-up spool. 3, a gear train for switching between deceleration and winding / rewinding; 4, a fork; C, a film cartridge; T, a recording track for recording data such as exposure status and frame number as magnetic information. (Magnetic storage unit), H is film F
A magnetic head 5 for writing information on the upper recording track T or reading recorded information therefrom is a pressing pad 5 for pressing the film F against the magnetic head H.

Reference numeral 7 denotes a battery for driving the entire system, 8 denotes a control circuit such as a microcomputer for controlling the entire drive, 9
Is a release switch for starting a photographing operation, 10 is a feeding circuit for winding and rewinding the film F, and 11 is a control circuit 8 for controlling a signal detected by the photoreflector 1 for feeding.
A pulse detection circuit 12 for converting the signal into a corresponding signal; a data writing circuit 12 for transmitting a signal for recording photographing information on a recording track T of the film F by the magnetic head H;
Reference numeral 3 denotes a magnetic reproducing circuit for processing a signal read by the magnetic head H and outputting the processed signal to the control circuit 8 as a reproduced signal;
Is an AE / AF / S that performs well-known photometry, ranging and shooting operations
It is an H circuit.

FIG. 3 is a flowchart showing the operation of the control circuit 8, and the operation from step 1 is started when the battery 7 is turned on. "Step 1" It is determined by a film presence / absence switch (not shown) whether or not the film cartridge C is loaded.
The process proceeds to step 2 by determining that the camera is loaded. "Step 2" The film feeding motor 2 is driven via the feeding circuit 10 to start winding the film F. "Step 3" The magnetic information prerecorded on the recording track T of the film F, for example, the film sensitivity, the prescribed number of frames of the film, etc., is reproduced by the magnetic head H and the magnetic reproducing circuit 13. The details of this operation will be described later with reference to FIG. [Step 4] The reproduced bit information is converted into a film sensitivity and a specified film number of frames and set in the camera. The details of this operation will be described later with reference to FIG. “Step 5” The part detected by the photoreflector 1
The movement signal is input through the pulse detection circuit 11, and it is determined whether or not the first frame of the film has arrived at the aperture position. "Step 6" The driving of the film feeding motor 2 via the feeding circuit 10 is stopped, and the winding of the film F is stopped. [Step 7] The reproduction of information by the magnetic head H and the magnetic reproduction circuit 13 is stopped. "Step 8" It is determined whether or not the release switch 9 has been turned on, and the process proceeds to step 9 by determining that it has been turned on. "Step 9" The AE / AF / SH circuit 14 is driven,
It performs well-known photometry, ranging, and photographing operations. That is, a series of photographing operations are performed. "Step 10" The film feeding motor 2 is driven via the feeding circuit 10 to start winding one frame of the film F. [Step 11] Here, the magnetic head H and the magnetic reproducing circuit 13 are driven to start writing of photographing information such as photographing date, shutter time, and aperture value on the recording track T of the film F being fed. . [Step 12] A perforation signal detected by the photoreflector 1 is input via the pulse detection circuit 11, and it is determined whether or not the second frame has reached the aperture position. The process proceeds to step 13 by making a determination. [Step 13] The driving of the film feeding motor 2 via the feeding circuit 10 is stopped, and the winding of the film F is stopped. "Step 14" Magnetic Head H and Magnetic Reproduction Circuit 13
Stops writing information. "Step 15" The frame number is counted up. [Step 16] The number of specified frames set in step 4 above, that is, the maximum frame number is compared with the current frame number counted up in step 15 and the current frame number is determined to be the maximum frame number. If the number has not been reached, the process returns to step 8 and the same operation is repeated. If the current frame number has reached the maximum frame number, the process proceeds to step S17. "Step 17" Here, the film feed motor 2 is driven in the reverse direction via the feed circuit 10, and the film F
Rewind. "Step 18" From the state of the film presence / absence switch (not shown), it is determined whether or not the film cartridge C has been taken out of the camera.

FIG. 6 is a diagram showing waveforms in each process from a read signal by the magnetic head H to the output of the signal as a reproduction signal, showing a comparison between the present embodiment and the conventional recording signal. It is.

FIG. 6C shows a signal read from the recording track T of the film F by the magnetic head H. This signal is a signal written at the time of recording as shown in FIG.
As this record information, as shown in FIG.
The plus side of (c) corresponds to the clock edge, and the minus side corresponds to the data edge. "1" and "0" depend on whether each data edge is closer to the front or back of the clock edge.
Is recorded.

FIGS. 6 (d) and 6 (e) are views showing the state when the plus and minus peaks of FIG. 6 (c) are detected in the magnetic reproducing circuit 13. FIG. D in FIG. 6 (e)
The dashed line 2 'indicates that the peak in FIG. 6C was small and could not be detected.

FIG. 6F shows a count value used to determine whether the data is "1" or "0". FIG. 6G shows the present embodiment. FIG. 6H and FIG. 6I show a conventional reproduction output when a signal as shown in FIG. 6C is read.

FIG. 7 shows a circuit section in the magnetic reproducing circuit 13 for detecting the signals shown in FIGS. 6 (d) and 6 (e).

In FIG. 7, reference numerals 71, 72, and 73 denote resistors which respectively generate reference voltages. Numerals 74 and 75 output pulse trains Cn and dn shown in FIGS. 6D and 6E, respectively.

Next, "reproduction" in step 3 of FIG.
Details of the operation will be described with reference to the flowchart of FIG.

In step 401, the first clock edge, that is, C1 in FIG. 6D is detected, and the process proceeds to step 402 by detecting this. Step 4
In step 02, the timer 1 is started and the next step 40
In 3, whether or not the first data edge has been detected;
That is, it is determined whether or not d1 in FIG. 6E has been detected, and if not detected, the process proceeds to step 412. Since this can be detected, step 404 is performed.
Then, the timer 1 is stopped. At this time, the timer 1 has counted "t1" in FIG. 6 (f).

Next, at step 405, the timer 2 is started, and at step 406, it is determined whether or not the next clock edge has been detected, ie, whether or not C2 in FIG. 6D has been detected. The process proceeds to step 407 by detecting this. In step 407, the timer 2 is stopped. At this time, the timer 2
This means that “t2” in (f) has been counted.

In step 408, the count values of the timer 1 and the timer 2 are compared, that is, "t1"
And “t2”, and here, “t1 <t2”
Then, the process proceeds to step 409. Here, the read data is set to "1" (see FIG. 6 (g)). Also, the count values of timer 1 and timer 2 are shown in FIG.
"T6>t7" like "t6" and "t7" in (f).
In other words, the count value of timer 1 is
If it is larger than the count value, the process proceeds to step 414. Here, the read data is set to "0" (see FIG. 6 (g)).

In step 410, the timer 1 is started. Then, in the next step 411, it is determined whether or not the reproduction of the information has been completed. If the reproduction has been completed, this routine is terminated and the process returns to step 4 in FIG. If not completed, step 4 is executed to read the next data.
Return to 03. Here, the process returns to step 403 again.

In step 403, it is determined whether or not the next data edge has been detected, that is, whether or not d2 'indicated by the broken line in FIG. 6E has been detected. However, since the reproduced signal output of the data corresponding to d2 'is small as shown in FIG. 6E, this d2' cannot be detected, and the process proceeds to step 412 here.

In step 412, it is determined whether or not the next clock edge has been detected, ie, whether or not C3 in FIG. 6D has been detected, and the process proceeds to step 413 by detecting this.

In step 413, since the data edge could not be detected, it is stored that 1-bit information was detected indefinitely, and the process proceeds to step 410. Here, FIG.
The count at t4 in (f) is started. The above-mentioned indefinite recording requires a state of "undefined" other than "0" and "1". For example, it is possible to assign two bits to one data. For example, “0” → “00”, “1”
→ “11”, “undefined” → “01”.

Conventionally, since no data edge is detected here, the magnetic reproduction information is erroneously output by one bit less as shown in FIG. 6 (h). However, in this embodiment, since "undefined" information is stored by detecting missing bits as described above, error-free data is stored as described below with reference to FIG. Can be reproduced.

FIG. 5 is a flowchart at the time of "film information setting" in step 4 of FIG. 3, and will be described in detail in accordance with the flowchart.

In step 501, an information start signal is searched for from the bit information sequence read out in step 3, and the process proceeds to step 502. In step 502, the number of bits constituting a series of data is input. Here, the number of bits may be up to the end signal or may be determined by a specified number.

In step 503, step 41 in FIG.
It is determined whether or not the information on the data edge detection error stored in step 3 contains undefined information. If there is no undefined bit, the process proceeds to step 507. If there is an undefined bit, the process proceeds to step 504.

In step 507, a horizontal parity check is performed. The horizontal parity is, for example, data in which the data is composed of 7 bits and an even or odd parity bit is given to the 8th bit. As a result, if the horizontal parity is satisfied, the process proceeds to step 506. If it is not satisfied, there is an error in the 8-bit data, and the flow advances to step 508 to correct the data based on the vertical parity.
The term "vertical parity" means that a sequence of "7 + 1" -bit data is arranged vertically and 8-bit data composed of a vertical parity is added to the final data. Therefore,
Bits where the horizontal parity error and the vertical parity error intersect can be corrected as reproduction failure bits. Note that the above steps 507 and 50
The operation 8 is a processing part which is generally performed.

If it is determined in step 503 that there is an undefined bit, step 50 is performed as described above.
The process then proceeds to step 4 to determine whether the data of the undefined part is "0" or "1" from the horizontal parity. If the parity bit is undefined, it can be obtained from 7-bit data.

In step 505, it is determined whether or not the data corrected in step 504 also satisfies the vertical parity. If so, the process proceeds to step 506, and if not, the process proceeds to step 509. Processing the next series of data as a reproduction error,
The same series of data is read again, and the process proceeds to step 510. Since the reproduction error in step 509 is an error only in the vertical parity, the error bit cannot be specified.

In step 506, the reproduced data is converted into specific information such as film sensitivity and number of sheets using the data table, and the flow advances to step 510.

In step 510, if necessary information is obtained, the process is terminated and the process returns to step 5 in FIG. 3. If not, the process returns to step 501.

FIG. 8 shows a main configuration of a second embodiment of the present invention, and shows an example of a circuit configuration for performing error discrimination of data edge detection during information reproduction.

Reference numerals 801 and 802 denote D flip-flops.
Tsu entered pulse train Cn shown in FIG. 6 (d) generated by di,
The reset terminal R, generated by the data edge 6
The ( dn ) pulse train of ( e ) is input. The Q output of the D flip-flop 801 is
To the D input terminal. The D input terminal of the D flip-flop 801 is held at a high level.

In the above configuration, FIG.
As shown in (e), the pulse d generated at the data edge
When the pulses C2 and C3, which are generated twice at consecutive clock edges without inputting 2 ', come from the output terminal A, "1"
Is output to notify that a data detection error has occurred. This information is stored as "undefined" as in the first embodiment.

According to each of the above embodiments, when reproducing the information magnetically recorded by the self-clock method, the data is reproduced.
Since the means for detecting the read error of the edge is provided, a signal having the error is not used as a correct reproduction signal in the subsequent circuit. In such a case, the process of restoring the read error portion is performed as described with reference to FIG.
Since "undefined" information is stored in the read error portion of the data edge and is restored by the parity bit, it is possible to output a correct reproduced signal without bit loss. Therefore, it is possible to realize a device capable of improving the reliability of reading information as a whole.

(Correspondence between the Invention and the Embodiment) In the illustrated embodiment, the magnetic head H corresponds to the magnetic head of the present invention, the comparator 75 in FIG.
The comparator 74 in FIG. 7 corresponds to the clock edge detecting means of the present invention, and the functional part of the control circuit 8 for executing steps 408, 409 and 414 in FIG.
The functional part of the control circuit 8 for executing steps 403 and 412 in FIG. 4 or the circuit in FIG.
The functional part of the control circuit 8 executing the step 413 corresponds to the information setting means of the present invention.

As described above, according to the present invention, Fi
The self-clocking method to the magnetic storage unit provided in LUM
A magnetic head for reading recorded information;
Data edge for detecting the data edge read by the data
Edge detection means, and a magnetic head read by the magnetic head.
Clock edge detecting means for detecting a lock edge;
Clock edge and data edge to be output and the data edge
Based on the time interval from one edge to the next clock edge
To set data and output it as a reproduced signal
A magnetic reproducing apparatus provided with a reproducing means;
The data edge by the data edge detecting means is contained in the generating means.
Discriminating means for discriminating a detection error of an image, and the discriminating means
If the data edge detection error is determined by
Sets information that a data edge detection error has occurred
Data setting means, the data edge
It is possible to provide a magnetic reproducing apparatus capable of outputting an accurate reproduction signal corresponding to the recorded information even when a detection error occurs .

[Brief description of the drawings]

FIG. 1 is a perspective view showing a main configuration of a camera according to a first embodiment of the present invention.

FIG. 2 is a circuit block diagram illustrating a schematic configuration of a camera according to the first embodiment of the present invention.

FIG. 3 is a flowchart showing the operation of the control circuit of FIG. 2;

FIG. 4 is a flowchart showing details of a reproducing operation in step 3 of FIG. 3;

FIG. 5 is a flowchart showing details of a film information setting operation in step 4 of FIG. 3;

FIG. 6 is a timing chart to help explain the operation in FIGS. 4 and 5;

FIG. 7 is a circuit diagram showing a configuration of a main part in the magnetic reproducing circuit of FIG. 2;

FIG. 8 is a circuit diagram showing a configuration of a main part in a second embodiment of the present invention.

[Description of sign]

 F film T recording track (magnetic storage unit) H magnetic head 8 control circuit 13 magnetic reproduction circuit 801 and 802 D flip-flop

Claims (1)

(57) [Claims] A magnetic head for reading the information recorded by the self-clock system to 1. A provided on the film magnetic storage unit, de read by the magnetic head - de detects the Taejji - and Taejji detecting means, by said magnetic head a clock edge detection means for detecting a clock edge to be read, the detected clock edge and de - Taejji and the de - Taejji based on a time interval until the next clock edge from the de - set the data which the reproduction signal a magnetic reproducing apparatus and a magnetic reproducing means for outputting as, in the magnetic reproducing means, the de - de by Taejji detector - discriminating means for discriminating, de by said discriminating means - - detection error of Taejji Taejji Is detected , a data edge detection error occurs.
A magnetic setting device for setting information indicating that the information has been read.