JP2590829B2 - Cassette tape recorder - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cassette tape recorder suitable for use in displaying time information corresponding to a running amount of a tape.

[Summary of the Invention]

According to the present invention, in a cassette tape recorder for displaying absolute time by calculating information related to a tape and rotation information of a drive system for driving the tape, time information is formed based on a pulse related to a rotating head for scanning the tape. Then, by interpolating and displaying the time information during the measurement of the information related to the tape, the time information is accurately displayed even during the measurement of the information related to the tape.

[Conventional technology]

A so-called linear counter used in a cassette tape recorder or the like calculates a tape travel amount by calculating information related to the tape, for example, the total length and thickness of the tape, and rotation information of a drive system for driving the tape, for example, a rotation cycle of a reel. The absolute time corresponding to is displayed. And
For a tape running speed such as R-DAT which is slow, it takes about 16 seconds to measure the entire length of the tape.

[Problems to be solved by the invention]

However, in the conventional cassette tape recorder, the linear counter does not count while measuring the entire length of the tape, and starts counting after the measurement is completed. Therefore, the linear counter cannot display the time corresponding to the tape running amount during the measurement of the entire length of the tape.

In order to avoid this, there is a method in which the linear counter performs counting based on a constant value during the measurement of the entire length of the tape. However, there is a drawback that the error is large and time information corresponding to the accurate tape running amount cannot be displayed.

The present invention has been made in view of the above, and an object of the present invention is to provide a cassette tape recorder that can accurately display time information even while measuring the entire length of a tape.

[Means for solving the problem]

The cassette tape recorder according to the present invention comprises, for example, rotation detecting means (18) and (19) for detecting the rotation periods T _S and T _T of the reels (13) and (16) as shown in the drawing, and the rotation detecting means (18) and (19). Tape length measuring means (30) for measuring the total length of the tape (10) based on the rotation periods T _S , T _{T of the} reels (13) and (16) detected in the above) and the running speed information of the tape (10).
Calculating means (31) for calculating time information based at least on the total length of the tape (10) measured by the tape total length measuring means (30); and a drum (11) around which the tape (10) is wound. Signal generating means (3) for switching the plurality of rotary heads HA and HB provided in the apparatus and generating a timing pulse SWP, and a time for forming time information based on the timing pulse SWP from the timing signal generating means (3) The information forming means (40) and the time information forming means (2
0) The time information from (40), the selecting means (32) for switching the time information from the calculating means (31), and the tape (1).
0) is measured by the time information forming means (2
0) Display the time information from (40), this tape (10)
And a control means (20) for controlling the selecting means (32) so as to display the time information from the calculating means (31) after measuring the total length of the calculating means (31).

[Action]

The information corresponding to the tape (for example, the entire length of the tape or the tape thickness) and the rotation information of the drive system for driving the tape (for example, the rotation cycle of the reel) are calculated by an arithmetic circuit (31), and the time corresponding to the running amount of the tape is calculated. Is obtained and displayed by the linear counter (34). At that time, the display is interrupted while measuring information related to the tape, for example, the total length of the tape. Therefore, the time information is formed based on the pulse (switching pulse) SWP related to the rotating head that scans the tape.
The time information is interpolated and displayed while measuring the total length of the tape. As a result, accurate time information can always be displayed even while measuring the entire length of the tape.

〔Example〕

Hereinafter, an embodiment of the present invention will be described in detail with reference to FIGS.

FIG. 1 shows the overall circuit configuration of this embodiment. First, the signal system will be described. At the time of recording, an input analog audio signal is band-limited by a low-pass filter (1), and then A / D, The digital signal is supplied to the D / A converter circuit (2) and converted into a digital signal. The digital signal is supplied to the encoder section of the error correction encoder and decoder circuit (3), where the signal is converted into a PCM signal for each block and interleaved and error corrected. , A block synchronization signal, a block address signal, and a subcode are inserted.

At the time of this recording, the switching circuits (4) and (8) are switched to the recording REC by the switching signal from the circuit (3) in synchronization with the switching of the circuit (3) to the encoder. From the circuit (3), a PCM audio signal obtained by time-compressing a signal corresponding to a half rotation of the head HA or HB of the audio signal to 90 ° rotation with a parity or the like added thereto is output from the rotation head HA.
And HB in the tape contact section,
This is alternately supplied to the rotary heads HA and HB via the switch circuit (4), the recording amplifier (5), the switch circuit (8) and the head changeover switch circuit (9), and the tape (1
0) It is sequentially recorded as one diagonal track on the top.

The head changeover switch circuit (9) uses the head changeover signal from the circuit (3) to supply a PCM signal time-compressed by 90 ° rotation to the head in contact with the tape (10). The mode is alternately switched between the A side and the B side every two rotations.

Next, at the time of reproduction, the switch circuits (4) and (8) are switched to the PB side by a switching signal from the circuit (3), and the head changeover switch (9) is set to one of the rotary heads HA and HB similarly to recording. Alternately to the side that comes into contact with the tape (10). The PCM signal reproduced from the tape (10) by the heads HA and HB is reproduced by the reproduction amplifier (6).
The data is supplied to a reproduction process circuit (7) via a, and is subjected to reproduction equalizer processing, bit synchronization is obtained, and is shaped into digital data, and a reproduction clock is obtained by a PLL circuit.

The PCM decoder from the reproduction process circuit (7) is supplied to an error correction encoder and decoder circuit (3). At the time of this reproduction, the circuit (3) functions as a decoder, and the PCM signal is decoded after error correction and the like.

The decoded signal is D / A of A / D, D / A converter (2)
The signal is returned to an analog signal in the converter section, and the audio signal is reproduced through a low-pass filter.

Next, a description will be given of a head drum and a tape running control system. (11) shows a drum, and two rotary heads HA and HB are separated from each other by 180 ° from the peripheral surface of the drum (11). Attached in a slightly protruding state,
The drum motor M ₁ typically is rotated in a predetermined direction at 2000rpm of rotating speed.

(12) the frequency signal proportional to the drum rotation speed than that in the rotation detector of the drum motor M ₁ (head speed)
D _FG and a signal D _PG indicating the head rotation phase are obtained.

(10) is a magnetic tape, which is drawn out of a supply reel (13), and is obliquely wrapped around a 90-degree angle range of a surface of a drum (11), and then is provided with a capstan (14) and a pinch roller (1).
5) It is wound up on the take-up reel (16).

Capstan (14) is rotated by a capstan driving motor M _2, the tape feeding.

(17) in the rotation detecting means of the motor M _2, which from the frequency signal C _FG proportional to the rotational speed can be obtained.

M ₃ and M ₄ are each reel motor for driving the reel (13) and (16), the rotational speed of the motor M ₃ and M ₄ each rotation detecting means (18) and (19) is detected, from which Frequency signal (rotation cycle) T _S proportional to the rotation speed
And T _T are obtained.

Also, (20) is a system controller (hereinafter abbreviated as syscon), (21) is a capstan and drum servo circuit, (22) is a reel drive control circuit, (23) is an arithmetic unit for reel drive control, 24) is a search control circuit, and (25) is a brake means.

(26) is an input device having various operation buttons,
(27) is a display for displaying tape running direction, recording / reproduction display, time information corresponding to the tape running amount of the program number, and the like.

A signal D _FG indicating the number of rotations of the rotary heads HA and HB from the rotation detecting means (12), a signal D _PG indicating the rotation phase, and a signal C indicating the rotation speed of the capstan (14) from the rotation detecting means (17). _FG is capstan and drum servo circuit (21)
Supplied to Then, the feed tape to the motor M ₂ together with the servo circuit (21) is the system controller (20) when the signal receiving and recording from and normal reproduction generates a signal for controlling the rotational speed and the circuit phase of the motor M ₁ Generates a signal that keeps the speed constant.

FIG. 2 shows parts directly related to the present invention.
Each part of the arithmetic unit (23) and the display (27) is shown in relation to the system controller (20). That is, in the figure, (30) is a tape length measuring circuit, (31) is an arithmetic circuit, and these are included in the arithmetic unit (23). (3
2) is a switch, which is included in the system controller (20), (33) is a drive circuit, (34) is a linear counter, and these are included in the display (27).

At the time of reproduction immediately after turning on the power supply or immediately after loading of the tape, or at the time of fast forward (FF) or rewind (REW), the entire tape length measuring circuit (30) measures the entire length of the tape. In the case of fast-forward or rewind, for example, the tape speed is set to a constant value in a 16-fold advance capstan running. In the tape length measuring circuit (30), reels (13) and (16)
The total length of the tape is measured based on information such as the rotation periods T _S and T _{T of} FIG. 1 and the tape speed. For a specific method for measuring the total length of the tape, see Japanese Patent Application No. 60-114696.

While measuring the entire length of the tape, the system controller (20) switches the switch (32) to the contact b side, and based on a pulse, ie, a switching pulse, related to the rotating head that scans the tape inside the system controller (20) as described later. The time information thus formed is supplied to a linear counter (34) via a drive circuit (33) so that the time information is substantially interpolated. The system controller (20) supplies the information to the arithmetic circuit (31) based on the time information to be interpolated.

Information on the total length of the tape measured by the tape length measuring circuit (30) is supplied to an arithmetic circuit (31).
Are supplied with information on the rotation periods T _S and T _T , where the running amount of the tape is calculated and converted into corresponding time information. When the measurement of the total length of the tape is completed by the tape length measuring circuit (30), this is transmitted to the system controller (20), and in response, the system controller (20) sets the switch (32) to the contact point a.
Switch to side. Then, as described above, the time information obtained by the arithmetic circuit (31) is supplied to the linear counter (34) via the drive circuit (33) and displayed based on the time information interpolated from the system controller (20). Is done.

In this way, switch (32)
Is switched to the contact b side so that time information is interpolated from the system controller (20), so that accurate time information is always displayed without interruption of time information even during measurement of the entire length of the tape.

FIG. 3 shows a means (40) for forming interpolation time information provided in the system controller (20). In the figure, (41) shows a pulse associated with a rotary head for scanning a tape. That is, an input terminal to which a switching pulse SWP (FIG. 4A) for switching the rotary heads HA and HB (FIG. 1) is applied, and an input terminal (41) is an input terminal of a D-type flip-flop circuit (42). The output terminal Q of the flip-flop circuit (42) is connected to the input terminal D of the D-type flip-flop circuit (43). The flip-flop circuits (42) and (43) detect an edge, for example, a falling edge of the switching pulse. Flip-flop circuit (4
The inverted output terminal of 2) is connected to one input terminal of the AND circuit (44), and the output terminal Q of the flip-flop circuit (43) is connected to the other input terminal of the AND circuit (44).

The output terminal of the AND circuit (44) is connected to the movable terminal c of the switch (45), and the contact a of the switch (45) is connected to the enable terminal EN of the 1/33 counter (46).
The contact b of 5) is the enable terminal EN of the 1/34 counter (47)
Connected to. Each ripple carry terminal RC of the counters (46) and (47) is connected to each input terminal of the OR circuit (48),
The output terminal of the OR circuit (48) is connected to the enable terminal EN of the 1/3 counter (49). Also, the respective output sides of the counters (46) and (47) are the contacts a and b of the switch (50), respectively.
The movable terminal c of the switch (50) is connected to the output terminal (51). From this output terminal (51), a minimum unit frame (F) of time information to be recorded in a subcode is extracted as described later.

The signal from the ripple carry terminal RC of the counter (49) is supplied to the switches (45) and (50) as a switching signal. The switches (45) and (50) are controlled by the counter (49) so as to be connected to the contact a for the first 2/3 period and to be switched to the contact b for the remaining 1/3 period.

The output end of the OR circuit (48) is a 1/60 counter (52)
And the ripple carry terminal RC of the counter (52) is connected to the enable terminal EN of the 1/60 counter (53) and the ripple carry terminal of the counter (53).
RC is connected to the enable terminal EN of the 1/24 counter (54). Then, the output terminals (55), (56) and (57) are taken out from the counters (52), (53) and (54), respectively, where the seconds (S), the minutes (M) and the hours (H) are respectively obtained. Time information is obtained. In addition, clock terminal (58)
The clock signal is more flip-flop circuits (42), (4
3), counters (46), (47), (49), (52), (5
3) and (54).

Now, when a switching pulse SWP as shown in FIG. 4A is supplied from the input terminal (41), its falling is detected by the flip-flop circuits (42) and (43), and the output of the AND circuit (44) is output. pulse signals S ₁ as shown in FIG. 4 B obtained on the side. The pulse signals S ₁ denotes an input terminal (4
Each time the switching pulse SWP is applied in (1), Fig. 4C
Are obtained continuously as shown in FIG.

The switches (45) and (50) are connected to the contact "a" for the first 2/3 period by the output of the ripple carry RC of the counter (49), and are switched to the contact "b" for the remaining 1/3 period. Therefore, in the first 2/3 period when the switches (45) and (50) are connected to the contact a, the counter (46) outputs the pulse signal S _1.
OR circuit (48) counting from 0 to 32
On the output side is generated 1st pulse signal S ₂₁ shown in FIG. 4 D is further a pulse signals S ₁ to the output side of the count to the OR circuit 0 th to 32 th (48) a 4
Second pulse signal S ₂₂ is generated as shown in FIG. D. During the remaining 1/3 period when the switches (45) and (50) are switched to the contact b side, the counter (47) outputs the pulse signal S
_{When 1} is counted from the 0th to the 32nd, the OR circuit (4
The output side of the 8) third pulse signal S ₂₃ shown in FIG. 4 D is generated. That is, when the pulse signals S ₁ example 100 the output of the AND circuit (44) appears, three pulse signals S ₂ appears on the output side of the OR circuits corresponding (48) thereto. This period is 3 seconds.

While the switch (50) is connected to the contact a, the output of the counter (46) is extracted as the minimum unit frame (F) (one rotation of the drum) of the time information recorded in the subcode, and the switch ( When 50) is switched to the contact b side, the output of the counter (47) is similarly extracted as a frame (F) (one rotation of the drum) of the minimum unit of the time information recorded in the subcode.

The pulse signal S ₂ obtained at the output side of the OR circuit (48) is
The signal is supplied to the counter (52) and divided by 1/60. As a result, an output corresponding to the second (S) of the time information is obtained at the output terminal (55). Also, the ripple carry terminal RC of the counter (52)
Is supplied to a counter (53) and frequency-divided by 1/60. As a result, an output corresponding to the time information minute (M) is obtained at the output terminal (56). Further, the output of the lip re-carry terminal RC of the counter (53) is supplied to the counter (54) and is divided by 1/24. As a result, the output terminal (57) has the time information (H).
Is obtained.

In this way, the time information of the hour, minute and second obtained at the output terminals (57), (56) and (55) is supplied to the switch (32) shown in FIG. It is supplied to the linear counter (34) through the drive circuit (33) through the contact b.

This circuit can also be used as means for forming time (program time, absolute time from the tape top, etc.) information for recording in the subcode area of the track. In this case, the above-mentioned frame (F) is used as a minimum unit (one rotation of the drum).

Time information for recording in the subcode area of the track is recorded in a format as shown in FIG. That is, the upper 4 bits of the pack PC1 are set to "0001" in the program time mode, and are set to "0010" in the absolute time mode. Lower 3 bits of Pack PC1, Upper 4 of Pack PC2
The program number is indicated by bits and lower 4 bits. In other words, in this case, the program number is 3 digits BC
Expressed in D code, lower 3 bits PNO-1 of pack PC1
Represents the most significant digit, the upper four bits PNO-2 of the pack PC2 represent the middle digit, the lower four bits PNO-3 represent the least significant digit, and the program numbers are represented from 001 to 799. Note that 000 indicates that the program number is not recorded, and OAA indicates that the program number is invalid.

X of the pack PC3 represents an index for the program number, and is represented by a 2-digit BCD code. For example, 00 represents a music interval (pause), 01 to 99 represent child division numbers, and AA represents that an index is invalid.

Pack PC4, PC5, PC6, PC7 are hour (H), minute (M),
Represents seconds (S) and frames (F), two-digit BC
Expressed in D code. For example, the hour (H) is 00-99, the minute (M) is 00-59, the second (S) is 00-59, and the frame is Is represented by

The pack PC8 is parity added by adding modulo 2 to PC1 to PC7.

〔The invention's effect〕

As described above, according to the present invention, during the measurement of the information related to the tape, the time information formed based on the pulse related to the rotating head that scans the tape is interpolated and displayed. It is possible to always display accurate time information even during measurement.

[Brief description of the drawings]

FIG. 1 is a circuit configuration diagram showing an embodiment of the present invention, FIG. 2 is a circuit configuration diagram schematically showing a main portion of the present invention, and FIG. 3 is a circuit configuration specifically showing a main portion of the present invention. FIG. 4 is a signal waveform diagram for explaining the operation of FIG. 3, and FIG. 5 is a diagram of a program time format recorded in a subcode area. (20) is a system controller, (23) is an arithmetic unit,
(27) is a display, (30) is a circuit for measuring the total length of the tape,
(31) is an arithmetic circuit, (32) is a switch, (33) is a drive circuit, (34) is a linear counter, and (40) is time information forming means.

Claims (1)

(57) [Claims] 1. A rotation detecting means for detecting a rotation cycle of a reel, and a tape total length measuring means for measuring a total length of a tape based on information on a rotation cycle of each reel detected by the rotation detecting means and information on a running speed of the tape. Calculating means for calculating time information based at least on the total length of the tape measured by the tape length measuring means; and timing for generating a timing pulse for switching a plurality of rotary heads provided on a drum around which the tape is wound. Signal generating means, time information forming means for forming time information based on a timing pulse from the timing signal generating means, and selecting means for switching between time information from the time information forming means and time information from the calculating means. During the period of measuring the total length of the tape, the time information from the time information forming means is displayed, and the total length of the tape is displayed. Hakanochi cassette tape recorder characterized by comprising a control means for controlling said selecting means so as to display the time information from said calculation means.