JP3066206B2 - Cassette tape identification method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a type of cassette tape having a different length (e.g., a detector for detecting the rotation speed of either one of a reel on a supply side and a reel on a take-up side). (Hereinafter referred to as the type of cassette tape) and a method of detecting the remaining tape time.

[0002]

2. Description of the Related Art In a conventional VTR, the type of cassette tape is determined by running the tape at a constant speed.
From the rotation detection sensors provided on both the take-up reel and the supply reel, measure the rotation cycle of each reel,
From this value, the winding area of the tape including the hubs of both reels is obtained, and this value is determined by using the property of having a unique value for each type of cassette tape (Japanese Patent Laid-Open No. 2-81389). The arithmetic expression according to this method is as follows. V: Tape speed (arbitrary set value) T _T : Reel rotation cycle of take-up side (measured value) T _S : Rotation cycle of supply side reel (measured value) R _T : Reel winding diameter (radius) of take-up side R _S : Supply-side reel winding diameter (radius) K: Eigenvalue (sum of the winding areas of both reels) depending on the type of tape The winding diameter of the take-up reel and the supply-side reel is calculated from the following set values and the measured values. Can do things. R _T = (T _T × V) / 2π R _S = (T _S × V) / 2π Therefore, the sum of the areas of the take-up reel and the supply reel
(K) can be expressed by the following equation. ^{_{K = π (R T 2 +}} R S 2) ----------- (A) = V 2 × (T T 2 + T S 2) / 4π ----------- (B) In this equation, since V and π are known, K can be obtained, and the value is compared with a unique value for each type of cassette tape to determine the type of cassette tape.

[0003]

The discrimination of the type of the cassette tape is a function required for two features of the VTR. The first feature is a display of the remaining amount of the tape. Various methods are used for calculating the remaining amount of tape, but basically, an accurate remaining amount of tape cannot be obtained unless the type of cassette tape is determined. The second feature is FF (fast forward)
/ REW (rewind). A problem in increasing the speed of the FF / REW is braking at the end of the tape. In other words, since the tape speed is increased by increasing the speed, if the same braking mechanism as in the past is used, the leader tape at the end of the tape cannot be fully braked, and in the worst case the tape may be cut . Therefore, it is necessary to determine the type of the cassette tape and to reduce the speed so as to stop safely when approaching the end of the tape. The conventional technology for discriminating the type of a cassette tape is basically thought of from the necessity of the tape remaining amount display function shown as the first feature, and the high-speed FF / R
The application to EW was a derivative of this. Therefore,
It has been difficult to increase the speed of FF / REW in a VTR in a popular price range such as a reproduction-only VTR that does not have a tape remaining amount display function. According to the present invention, in order to enable high-speed FF / REW even in a VTR in a popular price range, the discrimination of the type of the cassette tape is performed by one rotation provided on one of the supply reel unit and the take-up reel unit. It is intended to clarify the method to be performed using only information from the detector.

[0004]

According to the present invention, there is provided a method for determining the type of a cassette tape, comprising providing a rotation detector corresponding to either a take-up reel table or a supply reel table, and detecting a tape speed.
(V) A constant tape winding or rewinding is performed, a tape winding diameter (R _SENSOR ) of the reel is obtained from a measured rotation period (T _SENSOR ) of the reel on the rotation detector side, and the reel is rotated to the other reel. Period (T) The tape is transported in a constant state, and the set rotation period (T) of the reel at this time, the measured rotation period (T ' _SENSOR ) of the detector-side reel and the previously obtained tape speed (V) From the reel winding diameter (R _SENSOR ) of the rotation detector side obtained by constant tape winding or rewinding, the winding diameter (R) of the reel without the rotation detector is obtained, and the tape winding diameter (R) of both reels is obtained. _S E
_NSOR ) (R), the sum (K) of the tape winding areas of both reels is obtained, and K is compared with the characteristic value of each tape to determine the type of cassette.

[0005]

According to the present invention, the type of the cassette tape can be determined based on information from a rotation detector provided on only one of the supply reel and the take-up reel. In addition, in the conventional method, since the type determination of the cassette tape is a part of the remaining amount display function, it is difficult to increase the speed of the FF / REW with a popular model such as a playback-only machine in a VTR. . However, according to the method shown in the present invention, it is possible to increase the speed in at least one direction of FF / REW.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following description, during normal recording and reproduction,
The reel on the tape winding side is referred to as a T-side reel, and the reel on the tape supply side is referred to as an S-side reel. Tape winding means running the tape from the S side reel to the T side reel, and tape rewinding means running the tape from the T side reel to the S side reel.

First Embodiment As shown in FIG. 1, a rotation detector (3) is provided corresponding to the S-side reel among the S-side reel (1) and the T-side reel (2).
When detecting the rotation of the side reel (1). On the S side reel base,
By disposing the rotation detector consisting of optical sensors (3), S-side reel pulse P _S which period varies in accordance with the rotation of the S reel (1) is output. It should be noted that the reel pulse P _S is,
12 reels are generated each time the reel makes one revolution. Next, S-side reel pulse P _S is supplied to the S-side cycle counter (4). The S-side cycle counter (4) outputs the S-side reel pulse P _S
The clock of a fixed period generated from the clock generator (5) is counted while 12 clocks are generated, and the rotation period T _S of the S-side reel (1) is detected.

The calculation formula for discriminating the type of tape is shown below.
When the tape speed is constant, the S-side reel rotation cycle (T _S1 )
The radius (R _S ) of the side reel winding diameter and the tape speed (V) have the following relationship. V = 2πR _S / T _S1 Therefore, R _S is given by: R _S = V _S1 / 2π −−−−−−−−−−−− (C) Furthermore, in any tape transport system, the tape speed and Since the reel winding diameter and the reel rotation cycle have the same relationship on both the supply side and the winding side, the following equation is satisfied even when the rotation cycle on the winding side is constant. 2πR _S / T _S2 = 2πR _T / T _T −−−−−−−−− Therefore, the T-side reel radius (R _T ) is as follows. R _T = R _S × T _T / T _S2 −−−−−−−−− (D) By substituting the above equations (C) and (D) into the above equation (A), the unique value for each type of cassette tape is obtained. By comparison, the type of cassette can be determined.

FIG. 2 shows a flowchart of the first embodiment of the present invention. First, from the start (6) indicating the start of the discrimination of the tape, a block (61) for calculating the winding diameter (R _S ) of the S-side reel (1)
Enter. The block (61) performs the tape winding or rewinding operation at a constant tape speed, and thereby the S-side reel is operated.
(1) Rotation cycle (T _S1 ) and tape speed set arbitrarily
This is a block for calculating the winding diameter of the tape on the S-side reel from (V) using the above equation (C). Where S-reel winding diameter
When (R _s ) is obtained, the data is temporarily stored in the memory section (62), and the mode is switched from the block (63) to the next block (64). In this block (64), the T-side reel
(2) determining the winding diameter (R _T) of the. The method is to rewind the rotation of the T-side reel at a constant speed, thereby setting the rotation cycle of the T-side reel (2) and the rotation detector (3) provided on the S-side reel (1). Rotation cycle of S side reel (1) obtained by
By substituting (T _S2 ) and the winding diameter (R _S ) of the S-side reel (1) previously obtained and stored in the temporary storage section (62) into the equation (D), T
Obtain the winding diameter (R _T ) of the side reel. From the winding diameters (R _S ) and (R _T ) of the S-side and T-side reels thus determined, in the block (65), the eigenvalue of the cassette is obtained by using the above equation (A). Further, in block (66), block (6
In (7), the unique value table for each cassette tape has (A)
Inquire the result of the formula calculation to determine the type of tape.

Second Embodiment As shown in FIG. 3, a rotation detector (3) is provided on
When detecting the rotation of the side reel. FIG. 4 shows a second embodiment of the present invention.
4 shows a flowchart of an embodiment. First, from the start (7) indicating the start of discrimination of the tape, the process enters the block (71) for calculating the winding diameter of the T-side reel (2). This block (71) performs a tape winding or rewinding operation at a constant tape speed,
From the rotation cycle (T _T1 ) of the T-side reel (2) and the tape speed (V) arbitrarily set, the winding diameter of the tape on the T-side reel (2)
This is a block for calculating ( _RT ). Here the T side reel (2)
When the winding diameter (R _T) is determined, the data temporarily stored in the memory unit (72), through the mode switching block (73), enters the next block (74). In block (74), determining the winding diameter (R _S) of the S-side reel (1). The method is to rewind the S-side reel (1) at a constant rotation speed, so that the rotation cycle (T _S ) of the S-side reel (1), which is a set value, and the T-side reel (2)
From the rotation cycle (T _T2 ) of the T-side reel (2) obtained by the rotation detector (3) provided in the T-side reel and the winding diameter (R _T ) of the T-side reel previously obtained and stored in the temporary storage section (72). Winding diameter of S side reel (1)
(R _S ) is obtained. Incidentally, the similarly the relationship of _{R T = VT T1 / 2π R} S = R T × T S / T T2. From the reel diameters of the S side and the T side determined in this way, in the block (75), the unique value of the cassette is obtained by using the above equation (A). Further blocks (76)
In, the calculation result of the expression (A) is referred to the unique value table of various cassette tapes in the block (77) to determine the type of tape.

Third Embodiment The rotation cycle of the other reel is calculated from the tape running at a constant speed and the rotation cycle of a rotation detector (3) provided corresponding to one of the reels. From the cycle,
Each variable value can be specified also in the above equation (B),
The cassette can be determined. This will be described below. First, it is defined as follows. T _SENSOR : Rotation period of reel on rotation detector side (measured value) T: Rotation period of reel without rotation detector (calculated value) R _SENSOR : Reel diameter (radius) of reel on rotation detector R: Rotation detector V: Tape speed K: Sum of the tape winding areas of both reels Basically, the sum (K) of the area of both reels is obtained by the following equation as described above. K = π (R ² _SENSOR + R ² ) (A ′) The relationship between the rotation cycle of each reel and the winding diameter is as shown in the following equation. 2πR _SENSOR = V × T _SENSOR R _SENSOR = V × T _SENSOR / 2π −−−−−−−−−− (E) V = 2π × R _SENSOR / T _SENSOR −−−−−−− (E ′) 2πR = V × TR = V × T / 2π −−−−−−−−−−−−− (F) Therefore, when (E ′) and (F) are substituted for (A ′), the following equation is obtained. K = π ((V × T _SENSOR / 2π) ² + (V × T / 2π) ² ) = π ((V × T _SENSOR ) ² + (V × T) ² ) / 4π ² = V ² × (T ² _SENSOR + T ² ) / 4π −−−−−−−−−− (B ′) The formula (B ′) is the same as the above (B).

Next, a method of actually discriminating the type of the cassette tape using the equation (B ') will be described. The tape is wound or rewound at a constant tape speed (V), the rotation period (T _SENSOR ) of the reel on the rotation detector side is measured, and R _SENSOR is obtained from equation (E). The tape is conveyed to a reel having no rotation detector while the reel has a constant rotation period (T). At this time, the measurement rotation cycle of the reel on the detector side (T ' _SENSOR )
And the reel diameter (R _SENSOR ) of the detector-side reel previously determined by winding or rewinding the tape at a constant tape speed (V).
By substituting into the equation (E '), a constant tape speed (V') of the reel rotation period (T) is obtained. K is calculated by substituting T, T ' _SENSOR and V' for (B '). The type is determined by comparing K with the unique values of the various tapes.

Fourth Embodiment (Remaining Tape Calculation Method) Next, a description will be given of a method for calculating the remaining tape amount limited to REW or FF. Conventional tape remaining amount and usage time
Rotation detectors are provided on both the T-side reel and the S-side reel, and are calculated by the following equations (G) and (H).

[0014]

(Equation 2)

Here, r: reel hub radius t: tape thickness L: total tape length T _S : rotation cycle of the S side reel (measured value) T _T : rotation cycle of the T side reel (measured value) R _S : S side reel Tape winding diameter including reel hub R _T : Tape winding diameter including reel hub of T side reel

[0016] The tape usage time is

(Equation 3)

Is derived as The tape running speed V
Is specified by an instruction signal from a servo circuit that controls the rotation of a capstan that performs tape running during reproduction or recording. That is, in the case of NTSC, when an instruction signal indicating that the mode is the standard (SP) mode is given, V = 33.35 mm / sec, 2
In the double (LP) mode, V = 16.67 mm / sec, triple (E
In the P) mode, V = 11.11 mm / sec is substituted into the equations (G) and (H). Similarly, in the case of CUE (fast-forward playback) / REV (rewind playback), data corresponding to each mode is substituted into equations (G) and (H). The tape running speed V ₀ is the speed at which the user runs the tape on the PLAY or REC from the current tape position, and can be set arbitrarily by the user. Therefore, the tape running speed V ₀ is obtained by calculating the SP, LP, and EP data in the same manner as the tape running speed V described above.
(G) and (H).

The calculation of the remaining tape amount or the tape usage time is performed every time the rotation period T _S , T _{T of} the S-side and T-side reels is detected by the rotation detectors provided on the S-side and T-side reels. It is executed for each rotation of the S-side and T-side reels, and the user can arbitrarily select whether to calculate the remaining tape time or the tape usage time. However, in the above-described arithmetic expressions (G) and (H), the remaining tape amount and the tape usage time can be accurately calculated only in the constant speed running mode. And square of the rotational period TF _S, TF _T as a method for calculating the residual tape amount, and tape usage time, in all tape running mode from the operation circuit Yusuke the VTR in all tape running mode including a constant speed running mode, the tape The user can play the PLAY based on the reel hub radius r, the tape thickness t, and the total tape length L from the data designation circuit and the current tape position.
The tape running speed mode V ₀ for running the tape in (reproduction) and REC (recording) is substituted into an arithmetic expression described later, and the remaining tape amount or the tape usage time is calculated. Here, the remaining tape amount and the usage time are calculated by the following equations (I) and (J).

[0019]

(Equation 4)

Here, Tr: remaining time L: tape length r: reel hub radius t: tape thickness V ₀ : tape running speed in a mode in which the tape runs from the current tape position V: T _S and T _T are measured. Running speed of tape at the time T _S : Running at constant speed (PLAY, REC, CUE, REV
Etc.) S-side reel rotation period T _T : T-side reel rotation period during constant speed running TF _S : _S- side reel rotation period during non-constant speed running (FF, REW) TF _T : non-constant speed running The rotation cycle of the S-side reel at the time L, r, and t are constants specific to the cassette tape and are stored in the microcomputer in advance. The type of the cassette tape is determined by the value of T _S ² + T _T ² . V _{0 is} also a constant and is stored in the microcomputer in advance.

[0021] Incidentally, designated by an instruction signal from the external switch tape running speed V ₀ is adapted to be arbitrarily set user as described above (not shown), thus the tape running speed V ₀ is, SP 33.35mm / sec in mode, 16.67mm / sec in LP mode, 11.11mm / sec in EP mode
Is assigned to Further, when a non-constant speed running mode such as FF / REW is performed for the first time after the magnetic tape is mounted on the video tape recorder, the tape type is not determined, the reel hub radius r, the tape thickness t, and The total tape length L is unknown. Therefore, the mode is forcibly set to the constant-speed running mode, the tape type is determined, and then the mode shifts to FF / REW. The tape remaining amount or the tape usage time calculated as described above is displayed on a display (neither is shown) via the display control circuit. High-speed winding control is performed using the remaining capacity function. In order to prevent the tape end from reaching the end of the leader tape by the high-speed winding, it is confirmed that the tape end is approached by the remaining amount calculation value and deceleration is performed. When winding at high speed, T
The rotation speed of the side reel base is constant.

In the case of the above conventional example, in order to calculate the remaining amount, a rotation detector is required not only on the T-side reel base but also on the S-side reel base. Therefore, the cost increases, so that a low-cost model cannot include the remaining capacity function. Further, since the high-speed FF / REW uses the remaining capacity function, this function cannot be included.

The following will clarify a method of calculating the remaining amount by providing a rotation detector on one of the T-side reel base and the S-side reel base and limiting the rotation amount to REW or FF.
In the embodiment, a rotation detector is provided on the T-side reel base,
A method of calculating the remaining amount, limited to only W, will be described. The tape is run at a constant tape speed by recording, reproduction, fast-forward reproduction, or rewind reproduction, and the rotation cycle of the T-side reel (revolution detector-side reel) (T _{T in the above} formula (B)) is measured. REW is performed while the drive motor (capstan motor) rotation is constant. The motor rotation cycle Tm is controlled to be constant by the FG pulse of the drive motor. The reduction ratio from the drive motor to the S-side reel base is ε, and the rotation cycle T _S ′ of the S reel is given by the following (K)
It is calculated by the formula. T _S ′ = Tm / ε −−−−−−−−−− (K) where ε = S side reel base rotation speed / drive motor rotation speed At the same time, rotation cycle of T side reel (revolution detector side reel) (T _T ) ′ is measured. T _S is obtained from the following equation (L). T _S = TF _S = so _{T T · T S '/ T} T' ---- (L) T S 'T T is Motoma', determines the type of the tape are substituted into equation (B), (J ) Calculate the remaining amount by the formula.

If the tape position is not near the tape top, the high speed REW mode is entered. The rotation cycle of the S side reel base is measured from the equation (K), and is substituted into the equation (J) together with the rotation cycle of the T side reel to calculate the remaining amount as needed. When the tape position approaches the start of winding, the rewinding speed is reduced at a point where the remaining amount reaches a certain value. As described above, if the number of rotations is limited to only REW, the remaining amount can be calculated by the above-described method even when the rotation detector is not provided on the S-side reel base. Therefore, high-speed REW can be performed only with the rotation detector on the T-side reel base.

Conversely, the remaining amount can be calculated even if the rotation detector is provided only on the S side reel base and limited to only the FF. The tape travels at a constant tape speed by recording, reproducing, fast-forward reproducing or rewinding reproducing, and the S-side reel (rotation detector- side reel ).
Measurement ) . FF is performed while the drive motor (capstan motor) rotation is constant. The motor rotation cycle Tm is controlled to be constant by the FG pulse of the motor. Assuming that the reduction ratio from the drive motor to the T-side reel base is ε, the rotation cycle T _T ′ of the T-side reel can be obtained by equation (M). T _T ′ = Tm / ε −−−−−−−−−− (M) where ε = T side reel base rotation number / drive motor rotation number At the same time, the period T _S ′ of the S side reel pulse is measured. T _T is obtained by the equation (N). _{T T = TF T = T S} · T T '/ T S' ---- (N) since T _S 'T _T is Motoma', determines the type of the tape are substituted into equation (B), (J ) Calculate the remaining amount by the formula. If the tape position is not near the top of the tape, the apparatus enters the high-speed FF mode. The rotation cycle of the T-side reel base is measured from the equation (K), and is substituted into the equation (J) together with the rotation cycle of the S-side reel to calculate the remaining amount as needed. When the tape position approaches the start of winding, the winding speed is reduced at a point where the remaining amount reaches a certain value. The present invention is not limited to the configuration of the above embodiment, and various modifications can be made within the scope of the claims.

[Brief description of the drawings]

FIG. 1 is a block diagram of a first embodiment.

FIG. 2 is a flowchart of the first embodiment.

FIG. 3 is a block diagram of a second embodiment.

FIG. 4 is a flowchart of a second embodiment.

FIG. 5 is a block diagram of a conventional example.

[Explanation of symbols]

 (1) S side reel base (2) T side reel base (3) Rotation detector

Claims (3)

(57) [Claims] 1. A rotation detector is provided on one of a take-up reel side and a supply reel side to take up or rewind the tape at a constant tape speed (V), and to measure the rotation of the reel on the rotation detector side. From the period (T _SENSOR ), the tape winding diameter (R
_SENSOR ) and transfer the rotation cycle of the reel to the other reel.
(T) The tape is transported in a fixed state, and the set rotation period (T) of the reel at this time and the measurement rotation period of the detector-side reel
(T _'SENSOR) and the previously calculated tape speed (V) a fixed tape winding or rewinding said by the rotation detector reel tape winding diameter obtained (R _SENSOR), wound without a rotation detector reel Find the diameter (R) and calculate the tape diameter of both reels (R _SENSOR )
From (R), find the sum (K) of the tape winding areas of both reels, and
To determine the type of cassette by comparing the characteristic values of the tape and various tapes. 2. A rotation detector is provided on one of a take-up reel side and a supply reel side to take up or rewind the tape at a constant tape speed (V), and to measure the rotation of the reel on the rotation detector side. From the period (T _SENSOR ), the tape winding diameter (R
_SENSOR ), the tape is transported to the other reel in a state in which the rotation cycle (T) of the reel is constant, and the measured rotation cycle ( _T'SENSOR ) of the detector-side reel at this time and the previously obtained tape speed from (V) a fixed tape winding or rewinding said rotation detector side of the reel tape winding diameter obtained by (R _SENSOR), from _{V = 2π × R SENSOR / T} 'SENSOR, reel rotation period (T) constant tape speed of (V ') the _{determined, T, T' SENSOR, V} ' and ^{K = V' 2 × (T} '2 SENSOR + T 2) / 4π to by substituting the sum of the tape winding area of both reels (K) And calculating the type of the cassette by comparing K with the unique values of the various tapes. 3. A rotation detector is provided on one of a take-up reel side and a supply reel side to take up or rewind the tape at a constant tape speed (V), and to measure the rotation of the reel on the rotation detector side. The cycle (T _T ) is measured, and then the rotation cycle (Tm) of the drive motor is controlled to be constant, and the reel without the rotation detector is rotated at a high speed at a constant rotation cycle, from the drive motor to the reel without the rotation detector. The rotation cycle (T _S ') of the reel without the rotation detector is obtained from the reduction ratio (ε) of the rotation detector, and the rotation cycle (T _T ') of the reel on the rotation detector side is measured. T _S = T _T · T _S from '/ T _T', seek T _S, from T _S and T _T, to determine the type of the tape, Equation 1] And calculating the remaining amount of the tape. Here, L: tape length r: tape hub radius t: tape thickness V ₀ : tape running speed in a mode in which the tape runs from the current tape position TF _S : supply side reel at non-constant speed running (FF, REW) the period of the pulse TF _T: period of the take-up reel pulse at the time of Hijosoku traveling