JPS6234Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to an improvement in a malfunction prevention circuit for a data gap detection device particularly suitable for an automatic multi-track selection device for a tape recorder.

Recently, among tape recorders, so-called radio-cassette players, which have a built-in radio receiver, are rapidly becoming popular. Even in this type of tape recorder with radio, there is a demand for higher output, hi-fi, and multi-functionality.

On the other hand, in the field of audio equipment, there is a desire for something that can reflect the user's own participation preferences, and in particular, so-called karaoke is experiencing an unprecedented boom.

Therefore, there is a strong demand for a tape recorder with a radio as described above to be able to easily perform a karaoke function. In this case, it is possible to relatively easily handle this case using a conventionally known cue device and an automatic music selection device developed from the cue device.

However, it is not enough just to be able to support the karaoke function; it must also be able to operate reliably without malfunctioning in any situation.

By the way, conventionally known automatic song selection devices (mere cueing devices are also similar to this) essentially count the detection signals from the song interval detection section that detects the no-signal portion between songs, and detect the non-signal portion between songs. The tape recorder mechanism is controlled by driving an electro-mechanical conversion mechanism such as a plunger using a coincidence signal from a coincidence detection section that compares the counted value and a set value set in the track number setting section and finds a substantial match. By doing so, the desired song can be automatically selected. In this case, the automatic song selection operation described above will feed the tape at high speed (fast forward or rewind) until the specified song is reached, then stop the high speed feeding and switch to constant speed (playback) feeding. It has been done well.

In addition, such conventional automatic music selection devices automatically select only one song at a time, and the inter-music detection operation is performed only when the tape is being fed at high speed. However, it only serves the simplest function.

However, this has a serious drawback in that the song interval detection operation itself cannot often be performed reliably and malfunctions tend to occur. In this case, a conventional song interval (generally data interval) detection circuit consists of a saturation amplifier that amplifies the tape playback signal to the saturation level, a rectification circuit that rectifies the output signal of the saturation amplifier, and a rectification circuit that rectifies the output signal of the saturation amplifier. It is composed of a Schmitt trigger circuit that discriminates levels and converts them into pulse signals, and by using the level difference between the signal portion in a song and the non-signal portion between songs, a pulse signal is generated between songs. It was common for people to try to get it.

There are two reasons why such conventional inter-track detection circuits cannot reliably perform inter-track detection operations and tend to malfunction. This is caused by existing low-frequency noise such as hum. In other words, this reduced noise is reproduced at a fairly high frequency (approximately 3kHz) and at a high level during high-speed feed during song interval detection, so if it is left unreliable, it will not be possible to reliably detect the song interval, which may lead to malfunctions. The problem was that it tends to cause

Another cause is a problem related to the switching timing of the tape recorder mechanism that actually performs the switching operation, and is a problem that arises from the switching timing of the tape recorder mechanism that actually performs the switching operation. This is due to the fact that the operating timings of the mechanical system and the electrical system do not necessarily match when switching from (reproduction) feeding to high-speed feeding. In other words, the conventional inter-track detection circuit described above controls the tape recorder mechanism using its inter-track detection output (strictly speaking, a signal that matches the output of the setting section); Since the track detection circuit is configured to be controlled by an identification signal that is "1" during constant speed feed and "0" during high speed feed depending on the operating state, the operation of the mechanical system and electrical system is controlled. The problem was that if the timings did not match, malfunctions would occur.

Furthermore, a problem associated with these problems is that the electric power of the plunger, etc.
Another drawback is that so-called plunger noise, etc. that occurs when the mechanical conversion mechanism operates tends to cause malfunctions.

Incidentally, recent automatic music selection devices are required to be capable of performing advanced functions such as being able to select not only one song but many songs at a time, but this has further increased the problems mentioned above. At the same time, another problem unique to selecting multiple songs arises.
In other words, when automatically selecting only one song at a time, it was sufficient to perform the inter-song detection operation only during high-speed forwarding, but when selecting multiple songs, the inter-song section detection operation was performed only during high-speed forwarding. This is because, in addition to detection, it is also necessary to perform inter-musical detection during constant-speed feed, so it becomes impossible to simply deal with problems such as low-frequency noise such as hum that exists between songs as described above.

Therefore, this invention was made in view of the above points, and it is an improvement to prevent the malfunctions that arise from the above-mentioned conventional problems, especially related to the switching timing of the tape recorder mechanism. Therefore, it is an object of the present invention to provide an extremely good malfunction prevention circuit for a data gap detection device that can reliably perform a data gap detection operation under any conditions.

Hereinafter, with reference to the drawings, an embodiment of this invention will be described in detail, in which the invention is applied to an automatic multi-music selection device for a tape recorder.

First, to explain the data interval detection circuit associated with this invention, as shown in _FIG .
is supplied to the positive phase input terminal (+) of the Here, the saturation amplifier 11 is composed of an operational amplifier _A2 , whose negative phase output terminal (-) is grounded through a resistor _R1 and a capacitor _C1 in series, and is connected to the ground through a resistor _R2 . connected to the output end of the Further, the connection midpoint between the resistor R ₁ and the capacitor C ₁ is connected to the collector of the transistor TR ₁ via the capacitor C ₂ . Furthermore, the emitter of this transistor TR ₁ is grounded, and its base is at a level that is "1" in a constant speed feed state and "0" in a high speed feed state depending on the operating state of the tape recorder mechanism 16, which will be described later. Connected to the identification signal supply terminal IN.

Then, the above-mentioned resistors R ₁ , R ₂ , capacitor C ₁ ,
C ₂ and transistor TR ₁ are the saturation amplifier 11
In the illustrated case, the capacitances of capacitors C ₁ and C ₂ are set to satisfy the relationship C ₁ <C ₂ .

Thus, the saturation amplifier 11 to which the frequency characteristic determination circuit as described above is added is configured to perform the second operation according to the identification signal.
It will have frequency characteristics as shown in Figures a and b. That is, the tape recorder mechanism is now recording tape T.
is being sent at high speed, the identification signal is “0”
Therefore, the transistor _TR1 is turned off, and the frequency characteristic at that time is determined only by the capacitance of _{the capacitor C1} , as shown in figure _a . It is taking shape. In this case, for example, if the sizes of resistor R ₁ and capacitor C ₁ are determined so that F ₂ is 10kHz, then
This means that it has sufficient cut characteristics around 3kHz, which is related to the aforementioned low-frequency noise.

Therefore, if such a low-frequency cut-type frequency characteristic is applied to the saturation amplifier 11 to detect between songs in a high-speed feed state, low-frequency noise such as hum that exists between songs can be cut out as described above. Since it is possible to reliably distinguish between the signal part within a song and the no-signal part between songs, it is possible to eliminate the problems caused by low-frequency noise such as hum that exists when detecting between songs at high speed as in the past. It is possible to prevent the problem of not being able to detect between songs, and also the erroneous operation of not being able to perform a proper song selection operation.

In other words, the output of the saturation amplifier 11, which has a frequency characteristic that cuts out the low frequency range, is transmitted to the rectifier circuit 12.
and is applied to the Schmitt trigger circuit 14 via the time constant circuit 13, which generates a pulse-like signal that determines that it is between songs when the output level of the saturation amplifier 11 drops below a certain level. It is. Then, this pulse-shaped signal is waveform-shaped by the next waveform shaping circuit 15 to become a regular inter-track pulse, and then sent to a multi-track selection control circuit for an automatic multi-track selection device and a tape recorder mechanism control circuit 17, which will be described later. Supplied.

Furthermore, when the tape recorder mechanism is feeding the tape T at a constant speed, the identification signal is "1" and the transistor TR ₁ is turned on, so the frequency characteristics of the saturation amplifier 11 at this time are shown in Figure 2b. F ₁ = 1/2 determined by the capacitance of capacitor C ₁ + C ₂ as shown in
It has a cut-off frequency of πR ₁ (C ₁ +C ₂ ), which means that it has an almost flat shape. In other words, as mentioned above, since C ₁ < C ₂ , the frequency characteristics at this time are in a considerable resistance range (for example, from several Hz to several Hz).
10Hz).

Thus, during constant speed feeding, the saturation amplifier 1
The reason why the frequency characteristic of 1 is extended to a considerably low frequency range instead of having a low-frequency cut shape as in the case of high-speed feed is to prevent malfunctions that may occur when detecting between songs during constant-speed feed. This is to prevent this and ensure reliable music selection operations under any conditions. In other words, if the frequency characteristic of the saturated amplifier 11 is left in the low-frequency cut type when detecting between songs in a constant-speed feed state, as in the case of high-speed feed, then during a song This is because if a music signal containing only low frequencies is present, this will be mistakenly detected as being between songs. In other words, if the frequency characteristics of the saturating amplifier 11 are extended to a considerably low range during constant speed feed, even if there is a music signal in the low range only in a song, it will not be cut out. This makes it possible to reliably detect only regular gaps between songs without erroneously identifying them as gaps between songs.

That is, the data interval detection circuit as described above is substantially a signal part in a song or a non-signal part between songs in a song interval detection circuit such as the feedback loop of the saturation amplifier 11. A frequency characteristic determination circuit controlled by high-speed feed and constant-speed feed identification signals is added to the playback signal transmission path before the level discrimination section, which determines whether the song is a song by level discrimination. By automatically changing the frequency characteristics during playback signal transmission, such as cutting the low frequency range at times and extending it to a considerable low frequency during the inter-song detection operation in a constant speed feed state, it is possible to reliably reproduce the signal in any state. It is designed to be able to detect between songs.

Incidentally, in the above, the time constant circuit 13 is also controlled by the identification signal and the Schmitt trigger circuit 14 is controlled by the identification signal.
A small time constant is provided during high-speed feed and a large time constant is provided during constant-speed feed so that level discrimination can be performed stably in any state.
This allows the output of the rectifying circuit 12 to have a rising characteristic suitable for both high-speed feeding and constant-speed feeding, thereby making it possible to stably perform level discrimination.

Next, we will explain the circuit that prevents malfunctions related to the switching timing of the tape recorder mechanism as described above, which is the main part of this invention. It is equivalent. In other words, such malfunctions occur when the operating timings of the mechanical system and the electrical system do not match, such as when selecting another song from the middle of the playback of one song, as described above. (Reproduction) Even if the switch is made to high-speed feed in the middle of the feed, the tape recorder mechanism 16 itself is still in constant-speed feed without switching to high-speed feed due to a delay in the operation timing of the tape recorder mechanism 16. This is the case when only the identification signal becomes "0" at high speed in advance of this.

In other words, in such a state, the frequency characteristics of the saturating amplifier 11 are made into a low-frequency cut type as described above, and the time constant circuit 13 is also designed to provide a short time constant (approximately 100 msec). This is because a momentary drop in the playback signal level may be mistakenly interpreted as an interval between songs.

Furthermore, when detecting and switching between songs, the frequency characteristics of the saturating amplifier 11 are changed to suit any condition as described above, so malfunctions should not occur from the original point of view. However, malfunctions may occur due to blurring noise as described above.

Therefore, during a certain period after a signal for driving an electro-mechanical conversion mechanism such as a plunger in the tape recorder mechanism 16 is output, the electro-mechanical conversion mechanism operates, and until the tape recorder mechanism 16 is completely switched. By masking the inter-song detection output so that it does not occur, it is possible to prevent malfunctions caused by changes in the middle of song playback or plunger noise, and to ensure that the inter-song detection operation can be performed reliably under any conditions. The feature of this idea is that

That is, in FIG. 1, it is supplied from the multi-track selection control circuit and the tape recorder mechanism control circuit 17 for the purpose of selecting another song during the playback of a certain song (such as skipping song selection such as PLAY/SKIP to be described later). The motion control pulses are used to drive an electro-mechanical conversion mechanism such as a plunger of the tape recorder mechanism 16, and also to drive a malfunction prevention circuit 18 consisting of a mono-multivibrator.

As a result, the malfunction prevention circuit 18 supplies a mask pulse for masking during a certain period of time as described above to one end of the AND circuit 19. Here, the output of the waveform shaping circuit 15 described above is supplied to the other end of the AND circuit 19, but if there is an output of the waveform shaping circuit 15 due to the mask pulse described above, that is, an inter-song pulse due to misidentification. Regardless of whether or not this is the case, it will be masked for a certain period of time, so it is possible to prevent inter-song pulses from being output due to erroneous recognition.

FIGS. 3a and 3b show the operations without and with the malfunction prevention circuit 18 in contrast.
That is, in Figures a and b, A is the output of the time constant circuit 13 when the playback level momentarily drops due to the operation control pulse A, C is the output of the Schmitt trigger circuit 14, and U is the ′
is also the output of its waveform shaping circuit 15,
Up to this point, both figures a and b are the same. However,
After this, in the case of Fig. a, since there is no malfunction prevention circuit 18, a malfunction pulse is outputted, and as a result, an operation control pulse like E is outputted again, resulting in a malfunction.

On the other hand, in the case of figure b, the malfunction prevention circuit 18
Since there is a mask pulse like F, the malfunction inter-song pulse E and malfunction control pulse O like G and A are not outputted.

FIG. 4 shows a specific example of a certain period of time taken by a mask pulse generated by the malfunction prevention circuit 18, and shows at least about a period of time when the rising edge of an operation control pulse for driving an electro-mechanical conversion mechanism such as a is used as a reference time.
600msec is when it is necessary to mask. That is, in this case, the tape recorder mechanism 16 is switched from constant speed (reproduction) forwarding to high speed forwarding as shown in the figure after about 200 msec from the reference time, so if the identification signal changes from "1" to "0" during this time, Since the above-mentioned malfunction occurs due to the timing deviation, the certain period of time to be masked should be at least about 200 msec, and it seems that it should be selected to be about 300 to 400 msec, allowing for some margin.

However, depending on the configuration of the tape recorder mechanism 16, as shown in FIG. There is a risk that a portion where the reproduction signal stops may be mistakenly recognized as an interval between songs.

Therefore, in order to prevent malfunctions even in such a state, it is necessary to select a certain masking period of at least about 550 to 600 msec.

Here, the phenomenon in which the playback signal temporarily stops after switching from constant speed feed to high speed feed is due to the switching operation of the tape recorder mechanism 16, that is, the member that performs the switching operation between the high speed feed state and the constant speed feed state. In order to effectively transmit the applied bias force, an overstroke is given to each switching stroke of the member, but this overstroke amount is reduced on the side where high speed feed is converted to constant speed feed. This is because it is increased when converting from constant speed feed to high speed feed. In other words, if the overstroke amount is large when changing from constant speed feed to high speed feed, the amount of play will be correspondingly large mechanically, and this play will cause the magnetic head to temporarily detach from the tape surface. If the reproduced signal as described above is temporarily interrupted due to storage, the phenomenon described above will occur.

As mentioned above, the overstroke amount is set to be small on the side where high-speed feed is converted to constant-speed feed and large on the side where constant-speed feed is converted to high-speed feed. This is required because the switching time required for switching must be extremely short, about 30 msec at the most, and by setting it in this way, the changeover time between the high-speed feed and constant-speed feed of the switching member can be reduced. Even if the conversion cycle itself is constant, the timing of switching from high speed feed to constant speed feed can be set as short as possible so as to satisfy the above 30 msec.

FIG. 5 shows the switching member 20 set as described above.
This diagram schematically shows the overstroke relationship between the two. In other words, the switching member 20 is at a constant speed.
When changing from the PLAY state to the high-speed feed REW or FF state, the tip starts from the holding position A during playback, and even after the actual change is made at the A position, it continues to advance to the C position before stopping. , among these, the overstroke L ₁ is between A and C.
Also, when changing from high speed state to constant speed state,
The tip starts from the holding position C at high speed, and even after the actual change is made at the E position, it continues to advance to the A position before stopping, and the portion between E and A is overstroke L ₂ . . Here, L ₁
>L ₂ is set as described above.

Note that the switching member 20 is engaged at its base end with a cam 21 associated with a drive mechanism and an electro-mechanical conversion mechanism such as a plunger (not shown).
In conjunction with the forward and reverse rotation of 1, the two positions taken by the tip perform a mutual conversion action such that one of a constant speed mechanism and a high speed mechanism (not shown) is in an operating state and the other is in a standby state.

FIG. 6 shows a specific example of a song interval detection circuit equipped with the above-described malfunction prevention circuit 18. In this case, the rectifier circuit 12 is constituted by a transistor _TR2 . Further, the time constant circuit 13 is configured by a transistor TR ₃ controlled by an identification signal like the transistor TR ₁ described above, so that a resistor R ₄ is selectively connected in parallel to a circuit consisting of a capacitor C ₃ and a resistor R ₃ . Ru. The Schmitt trigger circuit 14 is composed of an operational amplifier _A3 and resistors _R5 to _R8 as shown in the figure, and the waveform shaping circuit 15 is composed of resistors _R9 and _R10.
consists of a capacitor C ₄ and a diode D ₁ . Note that the configuration of each part other than this is the same as that in FIG. 1, and the overall operation can also be explained in accordance with that in FIG. 1, so a description thereof will be omitted here.

FIG. 7 shows another example of the malfunction prevention circuit 18 described above, in which a mask pulse is supplied to the transistor TR ₄ instead of the AND circuit 19 for switching.

FIG. 8 shows a specific example of the case where the above-mentioned track interval detection circuit is applied to an automatic multi-track selection circuit of a tape recorder. That is, in this case, setting circuit 2
For example, 1,
3, 5, 7... The desired position setting information for multiple songs is set, such as after or before the song (selection of this is done mechanically on the tape recorder side). This position setting information is sent to the comparison circuit 23 and compared with the above-mentioned identification signal, and if the identification signal at that time is "1", that is, constant speed feed, a comparison output is output excluding the setting part at that time. , and if the identification signal is "0", that is, high-speed feed, only the setting section outputs a comparison output. The comparison output is determined by the control circuit 25 to match the count output obtained by counting the inter-song detection pulses detected as described above by the inter-song detection circuit 10 having the configuration shown in FIG. It will be done. If coincidence is not obtained during high-speed feeding, the plunger drive pulse is not outputted via the pulse shaping circuit 26, so the tape recorder mechanism 1
6 causes the high speed feeding state to continue. Then, if a match is obtained during high-speed feeding, a plunger drive pulse is issued, so that the tape recorder mechanism 16 is switched to a constant-speed feeding state and reproduction of the desired music piece is started. Note that if the comparison output is removed during constant speed feed and the setting is present, the plunger drive pulse will not be issued and the constant speed feed will continue as it is. 2, 3...
This is natural since the settings are made consecutively as in... Furthermore, when the comparison outputs outputted at the portions excluding the set portion during constant speed feed are apparently consistent, and the plunger drive pulse is issued, the tape recorder mechanism 16 is switched to high speed feed, From this point on, the same procedure as described above for high-speed feeding will be followed.

Here, the tape recorder mechanism 16 employs a mechanism that can alternately switch from high-speed feed or constant-speed feed to constant-speed feed or high-speed feed each time the plunger is driven. The same applies to the case of .

In addition, during this process, the song interval detection circuit 10 is provided with the above-mentioned malfunction prevention effect using the identification signal and the plunger drive pulse.

Next, the skip circuit 27 in FIG. 8 will be explained. This is the skip switch SW in the circuit.
It is possible to switch between high-speed feed and constant-speed feed at will by operating the . That is, by deriving the skip signal obtained by operating the skip switch SW via the pulse shaping circuit 271 and the OR circuit 272, the plunger drive pulse is output regardless of the presence or absence of the coincidence output, and the tape recorder mechanism 16 is activated. It is possible to switch between high speed feed and constant speed feed in any state. In this case, if you operate the skip switch SW in the middle of constant speed (playback) forwarding, you can skip over this at high speed even in the middle of the song (so-called SKIP/
PLAY) This is convenient because it allows you to move to the next set song (or the next song if it is not set).

Note that the above explanation has been given only for the case where it is applied to a multi-track selection device for a tape recorder, but it is not limited to this, and is applicable to ordinary single-track selection devices, simple cueing (including one-shot song selection) devices, and even tape handling devices. Can be widely applied to general equipment, as well as songs (music)
It goes without saying that various modifications and applications are possible without departing from the gist of this invention, such that other data different from the above may be used.

Therefore, as detailed above, according to this invention, any malfunctions that arise from the conventional problems, particularly those related to the switching timing of the tape recorder mechanism, can be completely prevented by being improved. Therefore, it is possible to provide an extremely good malfunction prevention circuit for a data gap detection device that can reliably perform a data gap detection operation even in a state where the data gap is detected.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an embodiment of the malfunction prevention circuit of the data interval detection device according to this invention, and Fig. 2 a and b show the frequencies of the saturation amplifier section in Fig. 1 during high-speed and low-speed feeding. Characteristic curve diagram, Figure 3 a, b
1 is a waveform diagram comparing the cases without and with the malfunction prevention circuit shown in FIG. 1, and FIGS. 4 a, b, and c are specific examples of determining the period of the mask pulse obtained from the malfunction prevention circuit shown in FIG. 1. FIG. 5 is a diagram illustrating the overstroke amount of the switching member, which is a cause of malfunctions prevented by the malfunction prevention circuit.
Fig. 6 is a wiring diagram showing an example of the circuit configuration shown in Fig. 1, Fig. 7 is a wiring diagram of main parts showing another example of the malfunction prevention circuit, and Fig. 8 is a tape to which this invention is applied. FIG. 2 is a circuit configuration diagram showing an automatic multi-music selection device for a recorder. T...Tape, H...Head, 11...Saturation amplifier, _R1 , _R2 ...Resistor, _C1 , _C2 ...Capacitor, _TR1 ...Transistor, IN...(Identification signal)
Input terminal, 12... Rectifier circuit, 13... Time constant circuit, 14... Schmitt trigger circuit, 15...
Waveform shaping circuit, 16... Tape recorder mechanism, 1
7... Multi-music selection control circuit and tape recorder mechanism control circuit, 18... Malfunction prevention circuit, 19... AND circuit.

Claims (1)

[Scope of utility model registration request] A tape recorder mechanism having an electro-mechanical conversion mechanism capable of mutually converting the tape into a high-speed playback state and a constant-speed playback state, and outputting first and second identification signals for identifying the high-speed playback state and the constant-speed playback state. and a frequency characteristic determining circuit is added which amplifies the reproduced signal from the tape in each of the reproduction states to a saturation level, and makes the frequency characteristic determination circuit a reduced cut type according to the first identification signal and a flat type according to the second identification signal. a saturated amplifier, a rectifier circuit that rectifies the output from the saturated amplifier,
A time constant circuit that gives a small time constant according to the first identification signal and a large time constant according to the second identification signal to the output from the rectifier circuit, and the output from this time constant circuit are level-discriminated. A data interval detection circuit obtains a data interval detection signal of the tape, and a converting drive signal is provided to the electro-mechanical conversion mechanism of the tape recorder mechanism in response to the data interval detection signal or a switching signal caused by an external operation. and a control circuit that outputs a control signal for preventing malfunction, and a control circuit that outputs a control signal for preventing malfunction, and at least the tape recorder mechanism is completely switched between a high-speed playback state and a constant-speed playback state based on the control signal for malfunction prevention from this control circuit. A malfunction prevention circuit for a data gap detection device, comprising a malfunction prevention circuit that masks an output from the data gap detection circuit for a predetermined period required for conversion.