JPS59144087A - Tape quantity detector - Google Patents

Abstract

PURPOSE:To obtain the output signal approximate to the actual feed quantity of a tape by integrating the normal integration data or the corrected integration data in response to the state of generation of pulses in accordance with the revolutions of feed and take-up reels respectively. CONSTITUTION:Four detection pulse trains P1 and P2 are generated from detection elements 10 and 11 for each revolution of feed and take-up reels 2 and 3 respectively and then supplied to a linearilty converting circuit 12. Then a counting circuit part 15 is triggered, and integration data S1 and S2 given from an output circuit 16 are added each other. In this case, a pulse sequence discriminating circuit 17 controls the circuit 16 so as to deliver the normal integration data through a counting circuit 13 or 14 when the detection pulses are generated alternately from reels 2 and 3 and to deliver the corrected integration data from the corresponding counting circuit when the detection pulses are continuously generated from the same reel respectively. Then accumulated outputs S4 and S5 are changed into tape feed quantity data signals S9 via a converting circuit 18 and supplied to a display device.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a tape amount detection device, and particularly to a device for displaying the amount of tape feeding in a tape device.

[Background technology and its problems]

In tape recording/playback devices such as video tape recorders and audio tape recorders, the current recording and playback status can be accurately determined by monitoring the remaining amount of tape from time to time during tape recording and playback. This is convenient for the operation of the tape recording device, and for this reason, the remaining amount of tape or the amount of tape to be fed is displayed using a tape amount detection unit (also called a tape counter).

Conventional tape counters of this type include mechanical counter types (those that reduce the rotation of the rotation mechanism of the supply reel or take-up reel using a gear mechanism with a predetermined gear ratio and display the count directly on a display ring rotation type counter); , tape counting method (reference pulse recorded on tape, e.g. C
TL pulses are reproduced by a head and counted by an electric counter circuit), and reel sensor type (which generates detection pulses according to the rotation of the supply reel or take-up reel and are counted by an electric counter circuit). However, each method has the following problems.

The No. 1K mechanical counter type has a complicated structure and is prone to failure, and it is difficult to make the display linear. Here, "linearizing the display" means converting the counter display into a numerical value proportional to the tape feed amount. Therefore, the smaller the tape winding diameter, the faster the speed will be (on the contrary, the larger the tape winding diameter, the slower the tape will be). In order to make it proportional to the feed amount, special conversion must be done. However, it is difficult to obtain this conversion mechanism with the mechanical counter type.

Secondly, although it is thought that the tape count system can obtain a linear tape count display in principle, there is a problem that it cannot be applied to a tape device that handles tapes that do not record reference pulses.

Furthermore, thirdly, in the reel sensor type, in order to obtain a linear tape count display, it is necessary to convert the non-linear change in the reel rotation speed as described above into a string-like change regardless of the winding diameter of the tape. I needed to do a conversion. This conversion operation is actually quite I! Since it uses a complicated arithmetic expression, the configuration of the arithmetic circuit inevitably becomes complicated.

[Purpose of the invention]

The present invention has been made in consideration of the above points, and it is possible to convert non-linear detection data into linear data using an extremely simple configuration in the above-mentioned reel sensor type tape amount detection device. This is an attempt to propose a tape counter.

[Summary of the invention]

In order to achieve this purpose, in the invention, the rotation detection pulse trains are obtained from the supply reel and the take-up reel, it is determined that they have a predetermined order with respect to each other, and the integrated data is calculated based on the determination result. He is busy accumulating the contents while changing them, and converting the accumulated results to the amount of tape displayed in time.

〔Example〕

Embodiments in which the present invention is applied to a cassette tape recorder will be described in detail below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a cassette tape, and rotation detectors 6 and 7 are provided in association with rotating shafts 4 and 5 connected to a supply reel 2 and a take-up reel 3. The rotation detectors 6 and 7 are, for example, rotors 8 and 9 having four blades F.
and a detection element 10 that is disposed opposite to the rotors 8 and 9 and generates one detection pulse each time the blade F passes.
and 11, and thus four detection pulse trains P1 and P2 are generated from the detection elements 10 and 11 every time the reels 2 and 3 rotate once. Here, as the rotation detectors 6 and 7, optical passage detectors, magnetic violation detectors, etc. that are known per se can be applied.In short, the blades F of the rotors 8 and 9 are connected to the detection elements 10 and 11. Any device that generates detection pulses P1 and P2 in response to each passing position may be used.

Detection pulses P1 and P2 obtained from detection elements 10 and 11 are provided to a linearity conversion circuit 12, respectively. As shown in FIG. 2, the linearity conversion circuit 12 has an integration circuit section 15 consisting of a supply reel side integration circuit 13 and a take-up reel side integration circuit 14.When each pulse of the corresponding detection pulse train P1 and P2 arrives, , the integrated data S1 and S2 provided from the integrated data output circuit 16 are cumulatively added.

The integrated data output circuit 16 outputs the integrated data from the integrated circuits 13 and 1 according to the content of the discrimination output S3 in the pulse order discrimination circuit 17.
The integrated data "10a" or "+b" is output to any one of 4 in 10,000. Here, the pulse order discriminating circuit 17 detects the detection pulse train Pi (third
The pulse generation mode of the detection pulse train P2 (Fig. 3 Q3)) arriving from the detection element 11 on the take-up reel side is constantly monitored, and detection pulses are generated alternately from the reel side different from the one that was generated previously. In this case, the & calculation data output circuit 16 is controlled so that the integration circuit on the side corresponding to the alternate detection pulses sends out the normal integration data "+a". On the other hand, if a detection pulse is generated continuously from the same reel side as the one that occurred before, the integration data is changed so that the integration circuit on the side corresponding to the continuous detection pulse sends out the corrected integration data "+b". Controls the output circuit 16.

Data output S4 cumulatively integrated into integration circuits 13 and 14
and S5 are added in the addition circuit 19 of the conversion circuit 18, and the addition result is provided as the tape feed amount data signal S7 to the tape length one hour conversion circuit 20VC. The conversion circuit receives the constant data signal S8 corresponding to the tape feed length per unit time and calculates the tape feed amount so that the tape feed amount is displayed in time (that is, in seconds). A division operation is performed on the data signal S7. This conversion result is sent to, for example, a display device as a tape counter output signal S9.

In the above configuration, for example, sections T1 and T2 in FIG.
When the supply reel-side detection pulse train P1 and the take-up reel-side detection pulse train P2 arrive alternately as shown in FIG.
The normal integration data "10a" is alternately given to the integration circuits 13 and 14 as integration data signals S1 and S2 for integration.

However, in the case of the third cause, when the supply reel side detection pulse P1 arrives successively at A jl e L2, the pulse order discriminating circuit 17 in response
3 to integrate the corrected integration data "10b".

Conversely, if the take-up reel side detection pulse P2 arrives successively at time t3 in FIG.
The 10th order discriminating circuit 17 integrates the corrected integration data "10b" of the integration circuit 11 on the following side.

Therefore, when the supply reel side detection pulse P1 and the take-up reel side detection pulse P2 are obtained alternately at the output end of the conversion circuit section (this means that the rotation speeds of the supply reel 2 and the take-up reel 3 are approximately equal). It is possible to obtain a tape counter output data signal S9 having content that is the arithmetic mean of the normal integrated data obtained based on these detection pulses. Also, from this state, if the detection pulses from one reel side start coming in succession (this means that the rotation speed of the one reel has become faster than the rotation speed of the other reel), this continues. A tape counter output data signal S9 having contents modified by the modified integrated data obtained based on the detection pulse can be obtained from the output end of the conversion circuit.

According to experiments, it has been confirmed that the content of the tape counter output data signal S9 obtained from the output terminal of the conversion circuit section is quite close to the actually measured tape feeding amount. j That is, the reel hub diameter is 16 (mm), the tape thickness is 13 [μm], and the tape length is 90 (m).
Normal integration data a is selected as a=6, corrected integration data b is selected as b=3, and conversion constant data signal S8 is set as 8.
When 8=35 is selected, the output data signal S9 has an error of about Dobe [seconds] when the tape amount is increased from O [seconds] to about 5000 C seconds as shown in Fig. 4. It merely showed that.

〔Effect of the invention〕

As described above, according to the present invention, detection pulses are obtained according to the rotations of the supply reel and the take-up reel, and when these two detection pulses occur alternately, normal integrated data is integrated, and one detection pulse is By summing the corrected summing data when ``flash'' occurs continuously, it is possible to obtain a tape counter output signal that closely approximates the actual tape feed amount, and as a result, the configuration of the arithmetic circuit is extremely simple. It is possible to easily obtain a tape amount detecting device that requires only a few steps.

[Brief explanation of the drawing]

Fig. 1 is a route diagram showing an embodiment of the tape amount detection device according to the present invention, Fig. 2 is a block diagram showing the detailed configuration of its linearity conversion circuit, and Fig. 3 is a signal waveform used to explain its operation. FIG. 4 is a chive cover-conversion error curve diagram showing experimental results. 1... Cassette tape, 2.3-... Supply, take-up reel, 6.7-... Rotation detector, 8.9... Rotor, 1
0°11...detection element, 12...linearity conversion circuit,
13, 14... Integration circuit, 15... Integration circuit section,
16-4% calculation data output circuit, 17... Pulse order determination circuit, 18... Conversion circuit, 19... Addition circuit, Addition... Tape length one hour conversion circuit. Applicant's agent 1) Megumi Be (11)

Claims (1)

[Scope of Claims] (a) Pulse generating means for generating first and second detection pulse trains according to rotation of the supply reel and take-up reel; (b) Pulses of the first and second detection pulse trains; (e) a determining means that determines that the first and second detection pulse trains have a predetermined order with respect to each other; d) an integrated data output means for sending the integrated data to the integrating means in accordance with the output of the determining means; (e) a converting means for converting the integrated output of the integrating means into a tape iK expressed in time. A tape amount detection device characterized by: