Tape transport system

Claim 2

A tape transport system comprising: a supply reel; a take-up reel; an upstream capstan; a downstream capstan; said capstans being positioned for guiding a tape from said supply reel to said take-up reel via said upstream capstan and said downstream capstan, and the rotational directions of both said upstream and downstream capstans coinciding with the running direction of said tape from said supply reel to said take-up reel; an upstream motor coaxial with and driving said upstream capstan at a peripheral speed which decreases at a rate with an increase in the load torque therein; and a downstream motor coaxial with and driving said downstream capstan independently of said upstream capstan and at a peripheral speed greater than the peripheral speed of said upstream capstan, and which peripheral speed decreases with an increase of load torque at nearly the same rate as said upstream capstan, whereby said tape, is transported substantially without slippage between said tape and said upstream and downstream capstans against the action of tension in said tape.

Claim 3

A tape transport system according to claim 1, further comprising speed control means coupled to said motors for controlling the peripheral speeds of said upstream and downstream capstans, said speed control means having two negative feedback loops, one for said upstream capstan and the other for said downstream capstan, said two negative feedback loops partially overlapping each other; and means coupled to said feedback loops for processing signals representative of the peripheral speeds of said upstream and downstream capstans separately by means of time sharing.

Claim 4

A tape transport system according to claim 2, wherein said two negative feedback loops comprise: two speed detecting means for detecting the peripheral speeds of said upstream and downstream capstans, respectively, and for producing speed signals representative of the speeds of said upstream and downstream capstans, respectively; two speed signal sampling gates respectively coupled to said two speed detecting means, for sampling said speed signals and producing sampled speed signalS for said upstream and downstream capstans, respectively; a pre-amplifying means coupled to said two signal sampling gates for amplifying said sampled speed signals and producing pre-amplified signals for said upstream and downstream capstans; two reference signal means for producing reference signals corresponding to predetermined speeds of said upstream and downstream capstans; two reference signal sampling gates respectively coupled to said two reference signal means for sampling said reference signals and producing sampled reference signals for said upstream and downstream capstans, respectively; a difference signal means coupled to said pre-amplifying means and said two reference signal sampling gates for comparing the pre-amplified signal for said upstream capstan with the sampled reference signal for said upstream capstan and producing a difference signal for said upstream capstan, and for comparing the pre-amplified signal for said downstream capstan with the sampled reference signal for said downstream capstan and producing a difference signal for said downstream capstan; a further amplifying means coupled to said difference signal means for amplifying said difference signals for said upstream and downstream capstans and producing amplified signals for said upstream and downstream capstans; two driving circuit gates coupled to said latter amplifying means for sampling said amplified signals for said upstream and downstream capstans, respectively, and producing sampled amplified signals for said upstream and downstream capstans, respectively; two driving circuits respectively coupled to said two driving circuit gates for said upstream and downstream capstans and also to said upstream and downstream capstans, respectively for controlling the peripheral speeds of said upstream and downstream capstans, respectively, in response to said samplied amplified signals for said upstream and downstream capstans, respectively; and a sampling signal means which is coupled to said two speed signal sampling gates, said two reference signal sampling gates and said two driving circuit gates for alternately producing sampling signals for said upstream and downstream capstans for alternately operating said two speed signal sampling gates, said two reference signal sampling gates and said two driving circuit gates in accordance with signal processing times of said gates, whereby said feedback loops operate on a time sharing bais.

Claim 5

A tape transport system according to claim 3, wherein each of said two driving circuits include a sample hold circuit for holding the sampled samplified signal for each of said upstream and downsream capstans produced during one sampling operation until a succeding sampling operation takes place, whereby said sampled amplified signal for each of said upstream and downstream capstans is held substantially constant until said succeeding sampling operation.

Claim 6

A tape transport system according to claim 3, wherein said two speed detecting means compose means for detecting the peripheral speeds of said upstream and downstream capstans as D.C. signals.

Claim 7

A tape transport system according to claim 3, wherein said two speed detecting compose means for detecting the peripheral speeds of said upstream and downstream capstans as time interval signals, and there is further provided a time interval measuring means coupled between said pre-amplifying means and each of said speed signal sampling gates for converting said time interval signals to D.C. signals.