JPH01130353A - Rotary head type magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To surely perform a control operation as prescribed by detecting a rotational frequency lower than a prescribed value to select and output a second reference signal having a prescribed frequency when the rotational frequency is lower than the prescribed value at the time of initial start due to power on or during high-speed searching. CONSTITUTION:A signal k1 indicating high-speed searching out of control data (k) outputted from a shift register 13 is inputted to one input of an OR gate 15, and a detection signal (m) is inputted to the other, and an output k2 is the select input of a selector 11. The selector 11 selects a control data reference signal (f) for the high-speed searching when this signal (f) is inputted at least once in a detection period T, but the selector 11 selects a control data reference signal (b) for normal reproducing when the reference signal (f) is not inputted at all by the stop of a rotating drum 102. Consequently, one of two reference signals (f) and (b) is selected and outputted in accordance with stop or rotation of the rotating drum 102. Thus, the operation state is obtained in a microcomputer 120 as prescribed.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is applied to, for example, a rotary head type digital audio tape recorder (hereinafter referred to as R-DAT). Two heads with different azimuth angles are installed at a rotational angle of approximately 180", and these two heads compress the time axis of multiple digital signals and transfer them onto the magnetic tape in the longitudinal direction. The present invention relates to a rotating head type magnetic recording/reproducing device which records to form a track and reproduces the recorded signal by expanding the time axis.

[Prior Art] Figure 3 shows an example of a rotary head type magnetic recording/reproducing device.
- It is a block diagram showing the 4R configuration of the signal processing system of DAT, and in the same figure, (102) is a rotating drum, (tol
a) and (101b) are rotating heads, and the above-mentioned rotating drum (
102) are mounted on the head at a rotation angle of 1806, and the azimuth angle of one head (101a) is set to plus 20", and the azimuth angle of the other head (101b) is set to minus 20". .

(104) is a magnetic tape, and the rotating drum (102)
(105) is a head changeover switch that alternately supplies a recording current to both heads (101a) and (101b) and alternately outputs a reproduction signal. obtain.

(103) is a Hall element, and this Hall element (103)
is a drum motor (
122) is mounted on the rotating shaft (122a) of the MS
As shown in FIG. 4(a), a pulse signal generated every rotation of the rotating drum (102) is obtained. (123) is a servo circuit that controls the rotation of the rotary drum (102) and provides a pulse signal (
The head changeover switch (1) is activated by the head switch signal as shown in FIG.
05).

(107a) is a recording amplifier, and the head (101a)
.

A recording signal current is applied to (toib), and this recording amplifier (
A modulation circuit (108a) is connected to 107a).

(l lower b) is a reproduction amplifier, and the above head (101a)
.

A demodulation circuit (10ab) is connected to this reproduction amplifier (107b).

(106) is a recording/reproducing switch.

(116) and (117) are audio signal input terminals, (114) is an A/D converter, (111) is RAM, (
109) is a data bus, and the input terminal (116)
).

The L channel and R channel audio signals input from (117) are converted into digital signals by the A/D converter (114), and these digital signals are written to RAM (111) via the data bus (109). . (110) is an encoding/decoding circuit, and this encoding/decoding circuit (110) encodes the recorded data in the RAM (111) for error correction. Sub-coat information such as musical tones is added to the 8 bi
A tracking control signal etc. is further added to the data modulated by t~10 bits, and the amplifier (
107a).

(115) is a D/A converter; (118) and (119) are audio signal output terminals;
The reproduced signal obtained by 7b) is sent to the demodulation circuit (108b)
It is converted from 8 bits to 10 bits in RAM (
111). Thereafter, error correction in the data is performed in the encoding/decoding circuit (110), and the D/
It is converted into an audio signal by the A converter (115),
They are output as L channel and R channel audio signals from output terminals (118) and (119), respectively.

The series of signal processing for recording and reproduction as described above is controlled by signals generated by the clock generation circuit (113) based on instructions from the system control microcomputer (120). In addition, a control clock is supplied from the clock generation circuit (11:l) to the address generation circuit (112).
It operates A M (111) and is also used as an operating clock for the encoding/decoding circuit (11G).

Next, among the operations of the device with the above configuration, the magnetic tape (10
4) A so-called high-speed search operation will be described in which the cue operation of recorded data such as audio information recorded above is performed at approximately 200 times the normal playback speed.

Magnetic tape (10
4) Rotate the servo so that the relative speed with y! is almost the same as during normal playback. 5 (123) to the drum motor (1
22) Of the reproduced signals obtained during the high-speed search operation performed while controlling the rotation speed, subcode data recording the track number, time, etc. is output from the demodulation circuit (108b) and sent to the microcomputer (120). . This microcomputer (1
20) determines the beginning of the song and inserts the magnetic tape (1) at the desired position.
04) is stopped and returned to normal d-play, completing one song selection operation.

FIG. 4 is a timing chart showing operating conditions during normal reproduction and high-speed search, and the operation will be explained with reference to FIG.

When the rotating drum (102) is controlled by the servo circuit (123) during normal playback, the clock generation circuit (1
The frequency and phase of the servo reference signal (c) as shown in FIG. 4(c) obtained in step 13) and the pulse signal (a) obtained for each rotation of the drum obtained by the Hall element (103) match in frequency and phase. As such, the rotation of the drum motor (122) is controlled by the output signal from the servo circuit (123). At this time, a head switch signal (e) is generated by the pulse signal (a), and control is performed so that the frequency and phase of this head switch signal (e) and the servo reference signal (C) almost match. . However, there is some jitter in the head switch signal (e) due to uneven rotation.

In addition, as shown in Figure 4(d), SUB coat and PCM
The relationship between the reproduced signal consisting of the head switch signal (e), and the servo reference signal (C) is as shown in FIG.
1) The data write clock is generated, and the data read clock to the encoding/decoding circuit (110) is generated based on the servo reference signal (C), so data writing and error correction operations can be completed within a predetermined time. becomes possible. Here, by detecting both edges of the servo reference signal (C), a control data reference signal as shown by (bl) in FIG. 3 is generated in the clock generation circuit (113).

This control data reference signal (bi) is a reference signal for inputting subcode data (g) related to system control such as playback and stop of the system control microcomputer (120). The above microcomputer (120
) Subcode data (g) is transferred based on clock Ci) generated at ).

By the way, during high-speed search, control is performed to keep the relative speed of the rotating drum (102) and magnetic tape (104) constant, so the falling edge of the control data reference signal (b) generated from the servo reference signal (c) Etsuji,
It cannot be used as a control data reference signal (bl) for determining the data transfer start timing. Because servo control is performed at a constant relative speed, the frequency and phase of the servo reference signal (C) and the head switch signal (e), which is synchronized with the actual reproduction signal, do not necessarily match, and the rotating drum (102 This is because the frequency and phase of the head switch signal (e) vary as the rotational speed of the head switch signal (e) changes.

Therefore, during high-speed search, both edges of the head switch signal (e) are detected to create a high-speed search control data reference signal as shown in FIG. 4(f).
This control data reference signal (f) is
20) is used as a control data reference signal (bl) that determines the start of input of subcoat data (g).

FIG. 5 shows the two control data reference signals (C) in the clock generation circuit (113).

(f) shows the circuit portion that performs the switching, in which (4) is the input terminal for the head switch signal (e);
6) is a D type flip-flop, and the above terminal (4)
A head switch signal (e) is input from (5) is an input terminal for a clock (ck) having a sufficiently lower frequency than the head switch signal (e), and the clock (ck) input from this terminal (5) causes the flip-flop (6) to The switch signal (e) is triggered, and its output is input to the next stage tree flop (7) and also to the exclusive OR gate (8). Further, the flip-flop (7) is triggered by the clock (ck).

Its output is compared to the output of the flip 70 tube (6) and the -period of the clock (ck) is published, and the exclusive OR gate (
8). Therefore, the output signal (j) of the exclusive OR gate (8) is the head switch signal (e)
This is the signal that detects both edges of , and becomes high level when detected.

(9) is a counter, and the above output signal (j) becomes the reset input of this counter (9), and this counter (
9) performs a counting operation using the above clock (ck),
The output of the counter (9) and the clock (ck) are input to an OR gate (lO), and the output of this OR gate (one gate) is connected to the clock input of the counter (9). Therefore, if the clock (ck) is at a low level when the output of the counter (9), that is, the high-speed search control data reference signal (') is at a low level, the clock (ck) is at a low level.
ck) is input to the counter (9). This counter (
9) is the control data reference signal (
f) is an n frequency division counter that determines the width (Lw) of the low period, and its frequency division ratio is set to a width that allows the microcomputer (120) to read the amplitude (Lw) of the low period.

Here, the control data reference signal (f
) and the control data reference signal (b) during normal playback are input to the selector (11), and among the control data signals (k) output from the shift register (13), the signal (kl) indicating high-speed search = 0 is used. selected. The output (31,) of this selector (11) is the output terminal (1)
The signal is then output to the microcomputer (120) shown in FIG. Therefore, the falling edge of the reference signal (b) or (f) causes the input terminal (
2), the clock (i), and the input terminal (3), the control data (g) are input to the shift register (I3), and after serial-to-parallel conversion in this shift register (13), the control data is It is output as a signal (k) and used to control each part.

In addition, the output (1) of the selector (11) is the delay circuit (
12) and is used as a data output clock of the shift register (13).

By using the circuit shown in Fig. 5 configured as described above, the transfer of control data (g) from the microcomputer (120) is synchronized with the head switch signal (e) not only during normal playback but also during high-speed search. Since the signal processing is started regardless of the rotation of the drum (102), the subcode data such as the song number is processed using the control data (b) or (f) as a reference, and the subcode data such as the track number is Since the data is immediately transferred to the microcomputer (120) after the transfer of g), it is easy to interface the data with the microcomputer (120).

[Problem to be Solved by the Invention 1] According to the conventional rotating head type magnetic recording/reproducing device configured as described above, in the initial startup state when the power is turned on, a reference signal synchronized with the rotation speed of the rotating head is generated. was not output, so a predetermined operating state could not be obtained. To explain this in detail based on the circuit shown in Fig. 5, since there is no input of control data (g) from the microcomputer (120) to the shift register (13) at the initial startup, the output of this shift register (13) is is undefined, and therefore the input signal (kl) to the selector (11) is also undefined.

Also, during high-speed searches, especially when searching in the reverse direction, the rotating head may not turn. In this case, even if the reference signal is obtained, the head switch signal cannot be obtained, and therefore the predetermined operating state cannot be obtained. There was a problem.

This invention was made to solve the above-mentioned problems, and even if the head rotation stops or the rotation speed is less than a predetermined number of rotations at the time of initial startup when the power is turned on or during high-speed search, the predetermined operating state is maintained. An object of the present invention is to provide a rotating head type magnetic recording/reproducing device that can reliably produce the following information.

[Means for Solving the Problems] A rotating head type magnetic recording/reproducing device according to the present invention selects a first reference signal synchronized with the number of revolutions of a one-rotation head and a second reference signal having a predetermined frequency. and a detection means for detecting that the rotation of the rotary head is stopped or is below a predetermined rotation speed, and the selection means selects the second reference signal based on the detection result of the detection means. It is characterized by being configured to output.

[Function] According to the present invention, when the rotation of the rotary head stops or is below a predetermined number of rotations, especially when searching in the reverse direction, at the time of initial startup after turning on the power or during high-speed search, the above-mentioned The detection means detects this, and based on the detection result, a second reference signal having a predetermined frequency is selected and output. As a result, control data is transferred from the system control microcomputer in a predetermined manner, and the desired operating state is reliably controlled.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described based on the drawings.

The configuration of the signal processing system of the R-DAT to which the present invention is applied is the same as that shown in FIG. 3, so a description thereof will be omitted.

FIG. 1 shows the main circuit portion of the clock generation circuit (113) of a rotating head type magnetic recording/reproducing device according to an embodiment of the present invention. Components are given the same reference numerals and their descriptions are omitted.

In FIG. 1, (18) is a flip-flop, which uses the high-speed search control data reference signal (f) as a trigger input, and connects it to the subsequent flip-flop (19) to control the high-speed search control data. The presence or absence of the reference signal (f) is detected and the detection signal (m) is output. (15) is an OR gate, and one side of this OR gate (15) has a shift register (13).
A signal (kl) indicating a high-speed search is input from the control □ data (k) output from the
The detection signal (■) is input to the other, and its output (kl) becomes the selection input of the selector (11).

Next, the operation of the above configuration will be explained with reference to FIG.

First, a reset signal such as the one shown in FIG. 2(n) which becomes low level at a frequency lower than that of the head switch signal (e) is applied to the flip-flop only when the high-speed search signal (kl) is low level during a high-speed search. (18). In addition, the flip-flop (19) whose D input is connected to the output of this flip-flop (18) is shown in FIG. 2(p).
Input the trigger clock as shown in . Here, when the high-speed search signal (kl) is at a low level, the period from the input of the reset signal (n) to the input of the trigger clock (p) is defined as a detection period (T), and this detection period (T) is, for example, It is set to correspond to one and a half revolutions of the rotating drum (102).

If the selector (11) selects the high-speed search control data reference signal (f) when the rotating drum (102) stops rotating, first the reset signal (n) is selected.
As a result, the output (q) of the flip-flop (18) becomes high level, and the rotating drum (1) is turned on within the above detection period (T).
Without the reference signal (f) to stop the clock (p), the flip-flop (18) is not triggered and the clock (p)
As a result, the output of the flip-flop (19) also becomes high level. When this happens, the detection signal (m) becomes high level, the select input (kl) of the selector (11) is also forced to become high level, and the normal control data reference signal (b) is selected and output.

Next, when the rotating drum (102) rotates, the high-speed search control data reference signal (f) is input to the flip-flop (18) within the above-mentioned detection period (T), and this flip-flop (18) is triggered. and its output (q) becomes low level. This is latched by the subsequent flip-flop (19), and the detection signal (K) becomes low level. Therefore, the select input (kl) of the selector (11) also becomes low level, and the control data reference signal (f) is selected during high-speed search. Then, at the beginning of the next detection wJ#11 (T), the output (q) of the flip-flop (18) becomes high level due to the reset signal (n), but the output (q) becomes high level due to the trigger by the reference signal (f). ) returns to the low level, the next stage flip-flop (19) latches the low level, and the selector (1
1) The select input (kl) is fixed at low level.

By repeating the above-mentioned operation, it will be detected that the control data reference signal (f) is input at least once during the high-speed search or during the initial startup after power-on during the above-mentioned detection period (T). , the selector (11) selects the reference signal (f), and the rotating drum (102)
If the reference signal (f) is not input once due to the stop of the control data reference signal (b) during normal reproduction, the control data reference signal (b) is selected.

Therefore, one of the two reference signals (f) and (b) is selected and output by stopping and rotating the one-rotation drum (102), so data can always be transferred by the microcomputer (120) as specified. You can get information about the operation status.

[Effects of the Invention] As described above, according to the present invention, the rotation of the rotary head may stop or fall below a predetermined rotation speed at the initial start-up when the power is turned on or during a high-speed search, especially when searching in the reverse direction. In this case, it is possible to detect this and select and output the second reference signal with a predetermined frequency.
Even in the above-mentioned case where a reference signal synchronized with the rotational speed of the rotary head cannot be obtained, control data can always be input to the control means based on the output of the second reference signal, and control operations can be performed as specified. can be carried out reliably. It also has the effect of reducing the burden on a control means such as a microcomputer, and making it easier to simplify the interface with the control means.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing the main parts of a clock generation circuit in a rotary head magnetic recording and reproducing apparatus according to an embodiment of the present invention, FIG. 2 is a timing chart explaining the operation of each part, and FIG. 3 is a block diagram showing the overall configuration of a rotating head type magnetic recording/reproducing device according to an embodiment of the present invention and a conventional example, FIG. 4 is a timing chart explaining the operation of the device shown in FIG. 3, and FIG. 5 is a conventional example. FIG. 2 is a configuration diagram showing the main parts of the clock generation circuit of FIG. (6), (7), (18), (19) -...Flip-flop, (9)...Counter, (10), (15)
-R gate, (l l)--Selector, (13)-
...shift register, (101a), (101b) one-rotation head, (102) ---rotating drum, (11:l
)... Clock generation circuit, (120) -... Microcomputer, (122) -... Drum motor, (12:l) -
...Servo circuit. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] (1) selection means for selecting a first reference signal synchronized with the rotational speed of the rotary head and a second reference signal having a predetermined frequency according to the operating state of the magnetic recording/reproducing device; a detection means for detecting that the magnetic recording/reproducing apparatus is stopped or the number of revolutions is below a predetermined number; and a control means for outputting a signal instructing the operating state of the magnetic recording/reproducing apparatus or setting the operating state based on the output signal of the selecting means. A rotary head type magnetic recording and reproducing apparatus, characterized in that the selection means is configured to output a second reference signal based on the detection result of the detection means.