Winding – tensioning – or guiding – Unwinding and rewinding a machine convertible information... – Carrier speed or tension control
Reexamination Certificate
2000-05-11
2002-09-17
Walsh, Donald P. (Department: 3653)
Winding, tensioning, or guiding
Unwinding and rewinding a machine convertible information...
Carrier speed or tension control
C242S334100, C242S334300
Reexamination Certificate
active
06450433
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an FF/REW control apparatus capable of performing high-speed FF/REW, a FF/REW control method and a medium in which an FF/REW control program is recorded.
2. Description of the Prior Art
Conventionally, in this type of FF/REW control apparatus, rotational periods of a video tape supply reel and a take-up reel are detected. Upon high-speed FF (Fast Forward) or high-speed REW (Rewind), a hub diameter is discriminated based on both rotational periods, and a tape running speed is controlled in accordance with the hub diameter. Generally, a VHS (Video Home System)-format video tape has either a hub diameter of 26 mm or 62 mm. If high-speed REW control or the like for a video tape having a hub diameter of 26 mm, (hereinafter referred to as a “thin hub”) is performed on a video tape having a hub diameter of 62 mm (hereinafter referred to as a “thick hub”), then the REW operation cannot be stopped at a tape end position, but rather further REW operation occurs. Accordingly, the tape transport speed is controlled in accordance with the hub diameter.
The hub diameter discrimination utilizes the fact that if the rotational periods of the supply reel Ts and take-up reel Tt are substituted into an expression:
A=Ts**
2+
Tt**
2,
“A” has a fixed value in accordance with hub diameter. That is,
If 3<A holds, then the hub diameter is 62 mm
If 1.8<A<3 holds, then the hub diameter is 26 mm
Thus, the hub diameter can be discriminated.
In the conventional apparatus, prior to high-speed FF/REW, a normal FF/REW is performed for several seconds, in order to detect the rotational periods of the supply reel and the take-up reel. Then, the above value A is obtained based on the detected values. The acceleration and deceleration upon high-speed FF/REW are then controlled in accordance with the hub diameter discriminated from the calculation.
On the other hand, Japanese Published Unexamined Patent Application No. Hei 3-95751 discloses performing the normal FF/REW for several seconds to detect the rotational speeds of the supply reel and the take-up reel prior to the high-speed FF/REW, and then calculating a ratio N between the rotational speeds. When the ratio N falls within a predetermined value range, a change rate is calculated based on the change of the ratio N over time. Utilizing the fact that the change rate of the ratio N differs for the case where the hub is out of specification and for the case where the hub is a thick hub, it is discriminated whether the hub is a thick hub or a hub out of specification (hereinafter referred to as an “out-of-spec hub”). The high-speed FF/REW is performed in accordance with the result of the discrimination. Further, deceleration is performed when the ratio N is either a predetermined or greater value or when the ratio N is a reciprocal of its initial value. Then, the FF/REW is terminated.
The above-described conventional FF/REW control apparatuses have the following problems.
In the former apparatus (where the hub diameter is discriminated by performing normal FF/REW for several seconds prior to high-speed FF/REW and control is performed in accordance with the hub diameter), when a user requests execution of high-speed FF/REW, the operating mode cannot be quickly shifted to the high-speed FF/REW mode. Further, because a software sequence is required to perform the hub diameter discrimination, a ROM capacity for this purpose is required.
On the other hand, in the latter apparatus, the rotational periods of the supply reel and the take-up reel are detected by performing normal FF/REW for several seconds prior to high-speed FF/REW, and the high-speed FF/REW is controlled in accordance with the ratio between these rotational speeds. In this control, since the rotational period ratio N is discriminated every time before high-speed FF/REW is performed, there is a possibility that in controlling a thin hub video tape, if FF/REW has been stopped once and is then performed again, thick hub control may be performed on the video tape.
Further, in this apparatus, in order to perform control in accordance with the respective hub diameters, the discrimination of the ratio N, the detection of time change of the ratio N, and the discrimination of whether or not the value of the ratio N is a reciprocal of its initial value, are made. Accordingly, in constructing this type of high-speed FF/REW apparatus, the processing load imposed by the software is heavy, and the necessary ROM capacity is large.
SUMMARY OF THE INVENTION
The present invention has been made in consideration of the above problems, and has as its objects to provide: a FF/REW control apparatus capable of performing high-speed tape forward (high-speed FF/REW) by a simple control, a FF/REW control method, and a medium in which a FF/REW control program is recorded.
According to the present invention, the foregoing objects are attained by providing a FF/REW (Fast Forward/Rewind) control apparatus comprising: a speed-variable tape forward mechanism, in which a video tape is loaded, for performing FF (Fast Forward) or REW (Rewind) control while variably controlling a tape running speed; a reel rotational-period detection unit for detecting rotational periods of a supply reel and a take-up reel of the video tape loaded in the speed-variable tape forward mechanism; a rotational-period-ratio calculation unit for calculating a rotational period ratio between the rotational periods of the supply reel and the take-up reel detected by the reel rotational-period detection unit; and a tape-forward control unit, capable of performing high-speed tape forward for the case where a hub diameter of the video tape is a thick hub diameter and for the case where the hub diameter is a thin hub diameter by controlling the speed-variable tape forward mechanism. The tape-forward control unit performs, upon FF/REW operation request, high-speed tape forward control for the case where the hub diameter is the thin hub diameter when the rotational period ratio calculated by the rotational-period-ratio calculation unit has a value other than values predetermined for the case where the video tape has the thick hub diameter.
In accordance with the present invention constructed as described above, when a video tape is loaded into the speed-variable tape forward mechanism and tape forward is requested, the reel rotational-period detection unit detects the rotational periods of a supply reel and a take-up reel of the video tape, and the rotational-period-ratio calculation unit calculates the rotational period ratio between the rotational periods of the supply reel and the take-up reel. Further, the tape-forward control unit is capable of performing high-speed tape forward for the case where the hub diameter of the video tape is the thick hub diameter and for the case where the hub diameter of the video tape is the thin hub diameter, by controlling the speed-variable tape forward mechanism. When FF/REW is performed in the FF/REW control apparatus, the rotational-period-ratio calculation unit calculates the rotational period ratio. If the rotational period ratio has a value other than values for a video tape having the thick hub diameter, the tape-forward control unit performs the high-speed tape forward control for the case where the hub diameter is the thin hub diameter.
In other words, the value range of the rotational period ratio of a video tape having the thick hub diameter overlaps with that of the rotational period ratio of a video tape having the thin hub diameter. Generally, as the amount of tape having the thick hub diameter is larger than that of a tape having the thin hub diameter, if the video tape having the thick hub diameter is subjected to the same control as the control for the video tape having the thin hub diameter, then even when a forward/rewind position approaches the tape end position, deceleration is not performed and stoppage in an appropriate position is not made. Accordingly, in order to avoid any inconvenience by performing
Crowell & Moring LLP
Funai Electric Co. Ltd.
Rodriguez Joseph
Walsh Donald P.
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