JP2628768B2 - Tape remaining amount display - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording / reproducing apparatus for recording / reproducing information on / from a tape-shaped recording medium, and relates to a tape remaining amount display apparatus for displaying a remaining tape amount. It is.

[Conventional technology]

The tracking servo system of a conventional rotary head digital audio tape recorder (hereinafter referred to as DAT) is to record a pilot signal divided into areas on a track and compare the crosstalk of pilot signals on adjacent tracks with the head during playback. Automatic Track Finding (hereinafter referred to as ATF), which performs tracking by using the ATF, is used.

FIG. 4 is a diagram showing a track pattern recorded on a DAT tape. As shown in FIG. 4, the DAT recording method employs an azimuth recording method in which two heads A and B having head gaps inclined in opposite directions alternately form tracks in the direction of arrow C. The track is + azimuth and the B track is -azimuth. Then, the tape is fed in the direction of arrow D. ATF1, A at both ends of the track
TF2 is a portion used for tracking, f1 is a pilot signal having a frequency of 130.67 KHz, f2 and f3 are two types of sync signals for detecting the pilot signal, and f4 is an earth signal.

Next, the principle of the ATF will be described with reference to FIG. Since the pilot signal f1 has a low frequency even when it is on an adjacent track, the pilot signal f1 enters the head as a crosstalk without being significantly affected by azimuth. The ATF makes use of this property. The width of the head is wider than the track pitch so that recording is performed while overlapping. When one head, for example, the head A traces the track A1, as shown in FIG.
First, the head A passes over the pilot signal f1. At this time, the sync signal f2 of the track A1 has not been detected. Next, the head traces the sync signal f2 and waits for the pilot signal f1. Then, as shown in FIG. 5B, the head A detects the pilot signal of the adjacent track B1, and sets its output level to VL. VL has a voltage level proportional to the amount of the head protruding from the track B1. After extracting the output VL, the head A similarly detects the pilot signal f1 of the adjacent track B0, and sets its output level to VR. If the head is completely under tracking control, the output level VL, VR
Becomes VL = VR (1). If the values of VL and VR are not equal, the head A does not accurately trace the track A1, and this difference is used as the difference in the amount of deviation from the track, that is, the tracking error. Further, it is determined which track is shifted from the magnitude relationship between VL and VR. And by ATF control, (1)
The tracking control is performed by adjusting the tape speed by applying feedback to the capstan motor so that the formula holds.

As shown in FIG. 6, the conventional tape remaining amount display device is provided with two heads A and B for recording and reproducing signals on a drum 1 around which a tape is wound.
Rotates to perform recording / reproduction by obliquely scanning the tape surface. The capstan 2 feeds the tape 3 at a predetermined control speed.
Scanning is controlled. Capstan FG which is a frequency generator (hereinafter referred to as FG) attached to capstan 2
Reference numeral 4 denotes a FG pulse which detects a voltage induced in a coil on the base by rotation of a FG magnet (not shown), and outputs the FG pulse to a capstan speed servo circuit 5 and a capstan phase servo circuit 6, respectively. The capstan speed servo circuit 5 compares the cycle of the FG pulse output by the capstan FG4 and outputs the result.
The output from the capstan speed servo circuit 5 and the capstan phase servo circuit 6 are the F output from the capstan FG4.
The G pulse and the reference signal are output after a time difference comparison. The adder 7 serves as a capstan phase servo circuit 6 during recording.
, And the output is given to the capstan motor 8. The tracking error detection circuit 9 outputs a head output during reproduction (hereinafter referred to as an envelope).
A signal for tracking is extracted from the control signal, and its output is supplied to an adder 7 via a switch 10.

At the time of recording / reproduction, the remaining tape amount is calculated based on the cycle of the reel FG pulse output from the reels FG13 and FG attached to the tape reels 11 and 12, respectively. For example, during the running of the tape, the cycle of the reel FG pulse of the tape supply reel 11 becomes shorter as the tape approaches the end, and the reel FG pulse of the winding reel 12 becomes longer on the contrary. The remaining tape amount calculating means 15 calculates the remaining tape amount based on the difference between the periods of the respective FG pulses from the supply reel FG13 and the take-up reel FG14, and supplies the display data to the microcomputer 16. The microcomputer 16 switches the changeover switch 10 to the terminal 10a during recording, and switches to the terminal 10b during reproduction. Tape remaining amount calculation means 1
The display data from 5 is subjected to arithmetic processing and given to the display 17 as a display signal.

Next, the operation at the time of recording / reproduction will be described. At the time of recording, the changeover switch 10 is switched to the terminal 10a side by a command of the microcomputer 15, and at this time, the capstan phase servo 6 compares the FG pulse from the capstan FG4 with the time difference and outputs the pulse to the capstan motor 8. The capstan motor 8 is driven by the sum of the output voltages of the capstan speed servo circuit 5 and the capstan phase servo circuit 6, and the capstan 2 rotates at a constant temperature. And tape 3
Tracks are recorded at equal intervals on the top. At this time, the capstan 2 is rotating at a constant speed, and both the tape running speed and the reels FG13 and FG14 are stable. As a result, the remaining tape amount calculating means 15 can accurately calculate the remaining tape amount, and the remaining tape amount is displayed on the display 17 via the microcomputer 16.

Even a track recorded at a constant speed during recording is not straight, but warps or bends due to the mechanism, accuracy, distortion, etc. Therefore, ATF control is required at the time of reproduction. At the time of reproduction, the microcomputer 16 is a changeover switch
10 is switched to the terminal 10b side, and the capstan motor 8 is driven by the sum of the output of the tracking error detection circuit 9 and the output of the capstan speed servo circuit 5. As long as the track is accurately recorded at the time of recording, the capstan 2 rotates at substantially the same speed as that at the time of recording even if a slight speed change occurs due to the ATF control. In this case, the remaining tape amount calculating means 15 can calculate the remaining tape amount almost accurately, and the display data of the remaining data is displayed on the display 15 via the microcomputer 16.

[Problems to be solved by the invention]

In such a conventional tape remaining amount display device, when tracking is controlled by the ATF at the time of recording or reproduction, the tape running speed is almost constant, so the pulse of the reel FG is stable. The calculation of the remaining amount of the tape can be performed almost accurately. However, if the envelope is lost during playback, ATF control cannot be performed. Therefore, the tracking error detection circuit 9 outputs an offset voltage, or outputs a previous hold voltage. Therefore, there has been a problem that the tape speed becomes unstable and it is difficult to accurately calculate the remaining tape amount.

The present invention has been made in view of such a problem of the conventional tape remaining amount display device, and has as its technical problem to be able to accurately calculate the remaining tape amount even when there is no envelope during reproduction. I do.

[Means for solving the problem]

The invention according to claim 1 is a tape remaining amount display device used for an information recording / reproducing device for recording / reproducing information on / from a tape as an information recording medium, and displaying a remaining amount of the tape being recorded or reproduced. Switching means for switching the running between tracking speed control and speed control by phase servo, a tracking error detection circuit for detecting a tracking error during reproduction and providing the output to the switching means, and an envelope detection for detecting the presence or absence of a head output during reproduction. The switching means is set to the tracking speed control side when the envelope signal is obtained from the envelope detection circuit at the time of reproduction and the phase is set at the time of recording or reproduction and the envelope signal is not obtained from the envelope detection circuit. The control means for switching to the speed control side by the servo and the rotation speed of the tape reel on the supply side and the winding side It is characterized in that it comprises a residual tape amount calculation means for calculating the residual tape amount, and a display device for displaying the residual tape amount obtained as the output of the remaining tape calculating means, the Te.

The invention according to claim 2 is a tape remaining amount display device used for an information recording / reproducing device for recording / reproducing information on / from a tape as an information recording medium, and displaying a remaining amount of the tape being recorded / reproduced. First switching means for switching the traveling of the vehicle to tracking speed control and speed control by phase servo; a tracking error detection circuit for detecting a tracking error at the time of reproduction and providing the output to the first switching means; A zero error voltage generating circuit for generating a voltage signal of the following, an envelope detecting circuit for detecting the presence or absence of a head output during reproduction, and a tracking control signal and an error zero voltage obtained from the zero error voltage generating circuit by an output of the envelope detecting circuit. A second switching means for providing a switching tracking error detection circuit; When the first signal is obtained, the first switching means is set to the tracking speed control side, and at the time of recording, the first switching means is switched to the speed control side by the phase servo, and the number of rotations of the tape reel on the supply side and the winding side. And a display device for displaying the remaining tape amount obtained as an output of the remaining tape amount calculating means.

[Action]

According to the first aspect of the present invention having such a feature, at the time of recording, recording is performed at a predetermined control speed, the remaining tape amount is calculated by the remaining tape amount calculating means, and the remaining tape amount is displayed on the display. I do. During playback, if the envelope is detected by the envelope detection circuit, it is played back at the tape speed of tracking control by the tracking error detection circuit, the remaining tape amount is calculated by the remaining tape amount calculation means, and the remaining tape amount is displayed on the display. I do. If no envelope is detected, the tape is played back at a predetermined control speed even during playback, the remaining tape amount is calculated by the remaining tape amount calculating means, and the remaining tape amount is displayed on the display via the controlling means. I have to.

According to the second aspect of the present invention, during recording, the running of the tape is controlled by speed control by phase servo. At the time of reproduction, when the envelope is detected by the envelope detection circuit, the head output is given to the detection circuit with a tracking error, and the running of the tape is controlled by the tracking speed control. If no envelope is detected, the output of the zero error voltage generation circuit is supplied to the tracking error detection circuit. Reproduction is performed at the tracking control speed, the remaining tape amount is calculated by the remaining tape amount calculation means, and the result is supplied to the control means to display the remaining tape amount on the display.

〔Example〕

A first embodiment of the tape remaining amount display device according to the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a tape remaining amount display device embodying the invention of claim 1;
The same parts as those in the above-described conventional example are denoted by the same reference numerals, and detailed description is omitted. In FIG. 1, a tape 3 is in contact with a drum 1 having two heads A and B for performing recording and reproduction. The capstan FG4 supplies the FG pulse to the capstan speed servo circuit 5 and the capstan phase servo circuit 6, respectively. The outputs of the capstan FG4 are added by the adder 7 and supplied to the capstan motor 8 as in the conventional example. During playback,
The sum of the output of the tracking error detection circuit 9 and the output of the capstan speed servo circuit 5 is given to the capstan motor 8. The remaining tape amount calculating means 15 is provided on the supply side reel FG13, respectively.
Then, the remaining amount of the tape is calculated based on the respective reel FG pulses from the take-up reel FG14, and is provided to the microcomputer 16.

The envelope detection circuit 21 integrates the outputs from the heads A and B during reproduction and discriminates the integrated signal to detect the presence or absence of an envelope. The output is supplied to the microcomputer 16. The microcomputer 16 switches the changeover switch 10 to the terminal 10a when no envelope detection signal is input from the envelope detection circuit 21 during reproduction. Thus, the capstan motor 8 is controlled by the capstan speed servo circuit 5 and the capstan phase servo circuit 6 at the same time of recording as during reproduction. The microcomputer 16 switches the changeover switch 10 to the terminal 10a side at the time of recording and supplies the display data provided by the remaining tape amount calculating means 15 to the display 17 in the same manner as in the above-described conventional example.

Next, the operation of this embodiment will be described with reference to the flowchart of FIG. When the power is turned on, the operation starts, and in step 31, the microcomputer 16 determines whether it is during recording or during reproduction. When the determination is made, the process proceeds to step 32, where the changeover switch 10 is switched to the terminal 10a side, and the speed is controlled by the capstan servo at the time of recording. Then, the remaining tape time is calculated by the remaining tape calculating means 15, and the remaining tape time is input (step 33). Next, the routine proceeds to step 34, where the display data is output to the display 17.
As a result, the remaining tape amount is displayed.

On the other hand, in the case of reproduction, the process proceeds from step 31 to step 35, where the envelope detection circuit 21 determines whether or not there is an envelope. If no envelope is detected, the process proceeds to step 32, where the same processing as during recording is performed. If the envelope is detected, proceed to step 36 and set the changeover switch 10 to the terminal 10
Switching to the b side, the capstan motor 8 is controlled by the capstan servo during reproduction. Then, the process proceeds to a step 33, where the same processing as the above-described recording is performed.

Next, FIG. 3 is a block diagram showing the overall configuration of a second embodiment of the invention according to claim 2. In the present embodiment, the same portions as those in the first embodiment described above are denoted by the same reference numerals, and detailed description is omitted. In this embodiment, a microcomputer
The switch 16 switches the changeover switch 10, which is the first changeover means, during recording and during reproduction. The envelope detection circuit 22 integrates the output from the heads A and B during reproduction,
A switch for detecting the presence or absence of an envelope by discriminating the integral output, and outputting the signal as a second switch means.
Give to 23. The changeover switch 23 switches between the signal from the head 1 and the output signal of the zero error voltage generation circuit 24 depending on the presence or absence of the envelope. Zero error voltage generation circuit
Reference numeral 24 denotes a signal for outputting a signal corresponding to a tracking error of zero. The output is supplied to a terminal 23b of the changeover switch 23. The tracking error detection circuit 9 has an ATF
An error detection signal is given to the changeover switch 10 by the control. Other configurations are the same as in the first embodiment.

Next, the operation of this embodiment will be described. At the time of recording, the changeover switch 10 is switched to the terminal 10a side, and the capstan 2 is rotated at a constant speed by the capstan speed servo circuit 5 and the capstan phase servo circuit 6, so that an accurate remaining amount of tape is obtained as in the conventional example. calculate. At the time of reproduction, the changeover switch 10 is switched to the terminal 10b by the microcomputer 16. When the envelope is detected by the envelope detection circuit 22, the changeover switch 23 is turned on by the envelope detection circuit.
Switching to terminal 23a is made by terminal 22. Then, as in the first embodiment, the output of the tracking error detecting circuit 9 is given to the changeover switch 10, the tape runs at the tracking control speed, and the calculation of the remaining tape amount is performed almost accurately.

If there is no envelope of the playback signal during playback,
The envelope detection circuit 22 switches the changeover switch 23 to the terminal 23b side, and the signal from the error example voltage generation circuit 24 is supplied to the tracking error detection circuit 9. With this signal, the capstan 2 can send out the tape at a constant speed, and the tape remaining amount calculating means 15 calculates an accurate tape remaining amount and displays it on the display 17.

〔The invention's effect〕

As explained in detail above, according to the invention of claim 1,
The tape runs at a predetermined control speed during recording, and AT
By running at the tracking control speed by the F control, and by running the tape at the predetermined control speed at the time of recording even when the envelope is interrupted, it is possible to calculate the accurate remaining tape amount.

According to the second aspect of the present invention, even if the envelope is interrupted during reproduction, the zero error voltage generating circuit outputs the same signal as when there is an envelope, so that the tape can be run at a stable speed. Therefore, there is an effect that the remaining tape amount can be accurately calculated regardless of the presence or absence of the envelope.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of a tape remaining amount display device according to a first embodiment of the present invention, FIG. 2 is a flowchart showing the operation of this embodiment, and FIG. 3 is a tape according to a second embodiment of the present invention. FIG. 4 is a block diagram showing the configuration of the remaining amount display device.
FIG. 5 is a track diagram showing the principle of ATF, and FIG. 6 is a block diagram showing the configuration of a conventional tape remaining amount display device. 2 ... Capstan, 4 ... Capstan FG, 5 ... Capstan speed servo circuit, 6 ... Capstan phase servo circuit, 8 ... Capstan motor, 9 ... Tracking error detection circuit, 10,23 ... ... Changeover switch, 13 ... Supply-side reel FG, 14 ... Rewind-side reel FG, 15 ... Tape remaining amount calculation means, 16 ... Microcomputer, 17 ... Display unit, 21,22 ... Envelope detection circuit , 24 ... Zero error voltage generation circuit.

Claims (2)

(57) [Claims] 1. Recording information on a tape as an information recording medium.
A tape remaining amount display device used for an information recording / reproducing device for reproducing and displaying a remaining amount of a tape being recorded or reproduced, a switching means for switching a running of the tape to tracking speed control and speed control by phase servo, A tracking error detection circuit that detects a tracking error during reproduction and supplies its output to the switching means; an envelope detection circuit that detects the presence or absence of a head output during reproduction; and an envelope signal from the envelope detection circuit during reproduction. Control means for switching to the speed control side by phase servo when the envelope signal is not obtained from the envelope detection circuit at the time of recording or reproduction and at the time of recording or reproduction, Remaining tape for calculating the remaining tape based on the number of rotations of the tape reel on the winding side Detecting means and the residual tape amount display device characterized by comprising a display unit that displays the remaining tape obtained as the output of the remaining tape calculating means. 2. Recording information on a tape as an information recording medium.
A tape remaining amount display device used in an information recording / reproducing device for reproducing and displaying a remaining amount of a tape being recorded or reproduced, wherein a first switching for switching the running of the tape to tracking speed control and speed control by phase servo. Means, a tracking error detecting circuit for detecting a tracking error at the time of reproduction, and providing the output to the first switching means, an error zero voltage generating circuit for generating a voltage signal with zero tracking error, and a head output at the time of reproduction. An envelope detection circuit for detecting the presence / absence of a signal; and a second switching means for switching between a tracking control signal and an error zero voltage obtained from the error zero voltage generation circuit by an output of the envelope detection circuit and providing the tracking error signal to the tracking error detection circuit. At the time of reproduction, when the envelope signal is obtained from the envelope detection circuit, the first switching is performed. Control means for switching the first switching means to a speed control side by phase servo at the time of recording; and a tape remainder for calculating a remaining tape amount based on the number of rotations of a tape reel on a supply side and a winding side. A tape remaining amount display device comprising: an amount calculating unit; and a display for displaying a remaining tape amount obtained as an output of the remaining tape amount calculating unit.