JPS58158066A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To detect intermusic gaps without reference to a tape speed, by arranging two heads at an internal shorter than the length between pieces of music on a tape, finding the tape speed from their outputs, and detecting intermusic gaps from a time difference corresponding to the speed of the tape. CONSTITUTION:For the tape 1 running as shown by an arrow 12, the heads 4 and 5 are provided at the interval shorter than the intermusic distance. The outputs of the heads 4 and 5 are inputted to a time difference detecting part 10 and detecting circuits 8 and 8' through waveform conversion parts 9 and 9'. The time difference detection part 10 finds the speed of the tape 1 from the time difference between the waveform converting circuits 9 and 9' to control response characteristics of the detecting circuits 8 and 8'. By the outputs of the detecting circuits 8 and 8', a command is supplied to a control circuit which is not shown in a figure to perform switching between a normal sound recording and reproducing mode and a stop mode. Thus, intermusic gaps are detected accurately without reference to the speed of the tape 1. During the backward run, they are detected similarly.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic recording and reproducing device, and its purpose is to control the response of detecting between songs of a signal recorded on a tape in accordance with the tape speed, thereby ensuring reliable An object of the present invention is to provide a device capable of detecting gaps between songs.

Conventionally, in magnetic recording and reproducing devices, a head is brought into contact with the tape while the tape is running at high speed, as in a cue/review operation, and the output of the head is rectified and smoothed to convert the waveform, and any interruptions in the output are detected. Was. However, since the tape drive at this time rotates either the take-up shaft or the supply reel shaft, the tape running speed is in a state where the tape running speed changes significantly as the amount of tape wound changes. For example, when a compact cassette tape is used, the tape speed during the track interval detection operation varies from 16 times to 33 times the normal tape running speed depending on the tape winding amount.

When the tape speed changes significantly as described above, even if the tape has gaps between songs of the same tape length, that is, no-signal sections, the time between the songs changes in accordance with the tape speed.

Therefore, if the response characteristic of the song interval detection circuit is set constant, it may not be possible to detect the song gap when the tape speed is high, and if the tape speed is not very fast, there may be a small period of time when there is no signal in the middle of the song. It had the disadvantage that it also detected sections and malfunctioned.

The present invention has improved the above-mentioned drawbacks by controlling the response characteristics of the inter-track detection operation in accordance with the tape speed.

FIG. 1 shows an embodiment of the basic configuration of this device.

The tape 1 is fed and returned from a supply reel 2 to a take-up reel 3 at high speed. The first head 4 and the second head 5 are installed at an interval shorter than the length of the interval between signals prerecorded on the tape 1. Still the first
The head 4 may be an erasing head, and the second head 5 may be a recording/reproducing head, or each may be a recording/reproducing head. The first head 4 and the second head 5 are in contact with the tape 1 when detecting the song interval, and the tape 1
Play back the recorded signal. The first song interval detection section 6 includes a waveform conversion circuit 9 that converts the waveform of the output of the first head 4, and a detection circuit 8 that detects a song interval based on the output of the waveform conversion circuit 9.
It consists of However, the second song interval detection section 7 is composed of a waveform conversion circuit 9' and a detection circuit 8', and the waveform conversion circuits 9 and 9' may have the same internal configuration, and the first head 4 and the second head 5 It may be changed according to the characteristics of Furthermore, the detection circuits 8 and 8' are also constructed based on the same concept.

The time difference detection section 1o detects the time difference between the output changes of the waveform conversion circuits 9 and 9', that is, detects the tape speed, and controls the response characteristics of the detection circuit 8 or 8'.

Then, the output of the first song interval detection section 6 or the second song interval detection section 7 gives a command to a control means (not shown), and the control means returns the tape speed to a constant state and performs recording/playback or Stop and switch to any operation.

Next, we will explain the detailed configuration and operation. FIG. 2 shows an example of the circuit configuration, and FIG. 3 shows an example of its input/output waveforms. The waveform conversion circuit 9 includes a comparator 911, a transistor 93. It consists of a resistor 94 and a capacitor 95. The output of the first head 4 is applied to one input terminal 9o of a comparator 91, and a reference voltage is applied to the other input terminal of the comparator 91. Therefore, the output of the comparator 91 is a positive voltage (hereinafter referred to as H level) when the input signal level from the first head 4 is higher than the reference voltage.
When the voltage is lower than the reference voltage, it becomes zero or a negative voltage (hereinafter referred to as L level). The transistor 93 becomes conductive when the output of the comparator 91 becomes H level, and becomes cut off when the output of the comparator 91 becomes L level. Capacitor 95 is charged from a power source (not shown) via resistor 94 when transistor 93 is in a cut-off state, and discharged for a short time when transistor 93 is in a conductive state. Now, assuming that the value of the resistor 94 is R+ and the capacitance of the capacitor 95 is C1, the voltage of the capacitor 96 is given by the time constant R+.
It is charged corresponding to X C+ and is instantly discharged if the impedance of the transistor 93 when it is conductive is ignored. Therefore, if the values of R1 and C+ are set larger than the time corresponding to the period of the AC signal, the voltage of the capacitor 96 will be almost zero during the period when the AC signal is output, that is, the L level, and the voltage of the capacitor 96 will be at L level, When the signal disappears, it is charged to H level.

This state is shown by the waveform in FIG. 3. Until the period t1 during which the signal (M) is applied to the comparator 91, the voltage of the capacitor 95 is at the L level as shown in (C). During the no-signal period from time t1 to t4, it is charged to H level, and its magnitude changes with time. When a signal is applied to the comparator 91 at time t4, it instantly returns to the L level. That is, the waveform conversion circuit e functions to convert the signal from the first head 4 into a waveform as shown in FIG. 3(C). Now, when the tape 1 is running at high speed in the direction of the arrow 12 as shown in FIG. Also, a time-delayed output is produced as shown in FIG. 3(B). The waveform conversion circuit 91 performs the same basic operation as the waveform conversion circuit 9 and produces an output waveform as shown in FIG. 3(E).

That is, a time delay corresponding to t2-t occurs between the outputs of the waveform conversion circuit 9 and the waveform conversion circuit 9'.

The outputs of the waveform conversion circuits 9 and 9' are then output to the time difference detection section 1.
o.

The time difference detection section 1o includes an amplifier 108 as shown in FIG.
and 1o9. Flip-flop 107p operational amplifier 1
03. It is composed of an integrating circuit consisting of a resistor 106 and a capacitor 104, transistors 102 and 106, and a capacitor 101. The output of the waveform conversion circuit 9 is supplied to the set terminal S of the flip-flop 107 via the amplifier 108, and at time t1 in FIG. 105 is driven to the cut-off state.Accordingly, the capacitor 10
4 is charged from the negative power supply via resistor 106. The voltage at the junction of the capacitor 104 and the resistor 106 is applied to the inverting input terminal of the operational amplifier 103.
An H level voltage is generated at the output of No. 3. The level increases over time due to a time constant corresponding to the product R2X02 of the resistance value R2 of the resistor 106 and the capacitance C2 of the capacitor 104. This operational amplifier 103
The output of is supplied to capacitor 1011C via transistor 102 which is in a conductive state. Next, when the output of the waveform conversion circuit 9' is generated at time t2 as shown in Fig. 3 @),
It is applied to the reset terminal R of the flip-flop 107 via the amplifier 109. Flip-flop 107 enters a reset state, driving transistor 102 to a cutoff state and transistor 106 to a conduction state. As a result, capacitor 104 is instantly discharged and capacitor 101 maintains a constant voltage. As shown in FIG. 3, the voltage level of the capacitor 101 is low when the time difference between time t1 and time t2 is small, and becomes high when the time difference is large. Since this time difference changes in accordance with the running speed of the tape 10, the voltage level of the capacitor 101 has a value proportional to the tape speed.

The detection circuit 8' is supplied with the voltage of the capacitor 1o1 as a reference voltage to one input terminal, and the output of the waveform conversion circuit 9' to the other input terminal.
When the output of capacitor 101 becomes greater than the output of capacitor 101, an output is generated. For example, if the voltage of the capacitor 101 is vl, as shown in FIG.
' output becomes larger than vl, and the detection circuit 8' becomes (F)
produces an output like

Similarly, the detection circuit 8 makes one movement and produces an output at time t5 as shown in FIG. The time difference between time t4 and time t2 or the time difference between time t3 and tl determines the important 4-hour element for the inter-music detection operation, and is generally set to about 3 seconds at a normal playback speed. That is, when the signal recorded on the tape 1 becomes zero for three seconds or more, it is assumed that a song has changed, and the no-signal portion is detected and used as an inter-song interval. Then, when the tape 1 is played back at high speed in the direction of the arrow 12, the output of the detection circuit 8 is used, and when the tape 1 is played back in the reverse direction, the output of the detection circuit 8' is used, or both can be used to detect between songs. can. On the other hand, when detecting between songs at high speed, if the pinch roller and capstan (both not shown) are rotated at high speed, vibration noise will be generated and the attributes will be large, so detect the gap between songs and immediately move on to the next operation. It is difficult to do this, and since the take-up reel is rotated at high speed, the tape speed changes depending on the amount of tape wound on the reel, and the time width between songs, that is, the no-signal period, changes depending on the tape speed. different. For example, in an example using a compact cassette, even if there is a 3-second gap between songs at normal playback speed, during high-speed song gap detection operation, the tape speed increases by about 16 times at the beginning of tape winding, resulting in a song gap of about 187 milliseconds. At the end of the tape winding, the tape speed increases by about 33 times, resulting in an inter-track time of about 91 milliseconds. If this is set to 91 milliJ seconds using one time constant circuit, if there is a no-signal period of approximately 1.6 seconds (converted to normal playback speed) at the beginning of tape winding, it will malfunction as an interval between songs. Put it away.

However, in the apparatus of the present invention, the time difference detection section 1o generates a voltage corresponding to the tape speed, and the detection circuits 8 and 8' compare the outputs of the waveform conversion circuits 9' and 9 and the output of the time difference detection section 10, respectively. Therefore, even if the tape speed changes, if there is a no-signal period of approximately 3 seconds when converted to the normal playback speed, the detection circuits 8' and 8 will generate an output, and the inter-track detection will be reliably detected. . For example, when the tape speed is not very fast at the beginning of winding, that is, the no-signal time becomes long, and as shown in 14-1 in FIG. Or 15-
1, the time difference is also large, and the output levels of the waveform conversion circuits 9' and 9 are also high. Therefore, the output level of the time difference detection section 10 also becomes high, and the detection circuits 8' and 8 produce an output at time t4 or t3, which corresponds to about 3 seconds in terms of normal playback speed. Conversely, if the tape speed is very fast, the steps 14-1 in FIG. Alternatively, the time difference between t5 and 4t2 becomes shorter, and the output levels of waveform conversion circuits 91 and 9 do not become very high. Since the output level of the time difference detection unit 10 does not become relatively high, the detection circuits 81 and 8 determine that if there is a no-signal period of approximately 3 seconds on the tape 1 (converted to the normal playback speed) as an interval between songs, and output the signal. respectively. In this way, the track intervals can be reliably detected without being affected by the tape speed.

The output of the detection circuit 8' or 8 gives a command to a control section (not shown), and the control section switches the device to normal recording, playback, or stop operations to complete the inter-music detection operation.

The above explanation explains how to take up tape 1 from supply reel 2 to reel 3.
I described a method for detecting between songs while fast forwarding to
A case will be described in which track intervals are detected while rewinding the tape 1 in the reverse direction at high speed.

The output terminal 96 of the waveform conversion circuit 9 in FIG.
to the output terminal 96' of the waveform conversion circuit 9' to the amplifier 108.
A similar operation can be obtained by connecting the detection circuits 8' and 8 to the control section respectively and supplying the output of the detection circuit 8' or 8 to the control section.

Although two detection circuits 8' and 8 are shown in FIG. 1, it is also possible to control the control section with the output of one of them and omit the other, which also allows the number of songs to be displayed using an electronic counter (not shown). Although it is also possible to use it as a drive signal, detailed explanation will be omitted.

Moreover, FIG. 1 and FIG. 2 are one embodiment of the present invention,
The configuration is not limited, and equivalent operations and effects can be obtained using other circuits or microcomputers.

Furthermore, in a two-head type device, the first head 4 and the second head 5 may use an erasing head on one side and a recording/playback head on the other, and in a three-head type device, one may use a recording head and the other may use a playback head. Although it is possible to realize this by using a head, and the apparatus can be constructed at a lower cost than when two read-only heads are used, the latter is also possible.

As described above, the apparatus of the present invention has a first song interval detection section, a second song interval detection section, and a time difference detection section, and the time difference detection section detects the first song interval detection section and the second song interval detection section. The tape speed is detected from the time difference between the outputs of the inter-track detection section.
Since the response characteristics of either or both of the inter-track detection section and the second inter-track detection section are controlled, it has the excellent effect of accurately detecting the inter-track interval without being affected by the tape speed. .

Furthermore, it is possible to use the heads that are originally attached to the apparatus as the first head and the second head, and the apparatus can be constructed at low cost.

[Brief explanation of drawings]

Fig. 1 is a block circuit diagram showing an embodiment of the basic configuration of the present invention, Fig. 2 is a circuit diagram of its main parts, and Figs. 3 (M) to (F).
is the same waveform diagram. 1... Tape, 4... First head, 6
...Second head, 6...First song interval detection section, 7...Second song interval detection section, 8.8'
...Detection circuit, 9.9'...Waveform conversion circuit, 1o...Time difference detection section. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 3 Figure 2t! 1

Claims (1)

[Claims] A first song interval detection section detects a song interval by waveform converting and time processing the playback output of the first head, and a second song interval detecting section detects a song gap by waveform converting and time processing the playback output of the second head. Depending on the time difference between the outputs of the song interval detection section, the first song interval detection section, and the second song interval detection section, either one of the first song interval detection section and the second song interval detection section or A magnetic recording/reproducing device characterized by comprising a time difference detection section that controls both response characteristics.