Magnetic tape readout system with means to generate artificial signals

Claim 2

In a data recording machine of the character described including a tape drive means and a timed drive circuit for said drive means, said circuit being put into operation in response to a tape move signal and including a leading edge and a trailing edge differentiator for said signal, a one shot delay flop in said circuit having a predetermined delay period, said delay flop having set and reset input lines connected respectively to said leading edge and trailing edge differentiators, said delay flop having an output line operably connected to said tape drive means for supplying a signal thereto, said leading edge differentiator causing said delay flop to set when a tape move signal occurs whereby said tape drive means is activated, said drive means remaining in operation for the full delay period of said delay flop at the end of which the delay flop automatically resets and the drive means is deactivated, said trailing edge differentiator being operable, when the tape move signal is of shorter duration than the delay period of said delay flop, to differentiate the trailing edge of said signal and force the delay flop to reset short of its own period, said tape drive means being deactivated when said delay flop resets.

Claim 3

A machine as defined in claim 1 wherein said drive circuit includes a differentiator for differentiating the trailing edge of the delay flop output signal to said tape drive means.

Claim 4

In a data recording machine of the character described including a drive capstan and a pinch roll engageable with said capstan to effect forward movement of tape, a timed circuit for controlling the operation of said pinch roll comprising a one shot delay flop operable when set to supply a signal to said pinch roll to cause engagement of same with said capstan, means for supplying a tape move signal to said circuit during the tape cycle of the machine, means responsive to the leading edge of the tape move signal to set said delay flop means responsive to the trailing edge of the tape move signal to reset said delay flop, said delay flop being automatically reset after a fixed period in the absence of said trailing edge means forcing it to reset in a shorter period, and means for differentiating the trailing edge of the delay flop signal to said pinch roll.

Claim 5

In a data recording machine of the character described including a drive capstan and a pinch roll engageable with said capstan to effect forward movement of tape, a timed circuit for controlling the operation of said pinch roll comprising a one shot delay flop operable when set to supply a signal to said pinch roll to cause engagement of same with said capstan, means for supplying a tape move signal to said circuit during the tape cycle of the machine, means responsive to the leading edge of the tape move signal to set said delay flop means responsive to the trailing edge of the tape move signal to reset said delay flop, said delay flop being automatically reset after a fixed period in the absence of said trailing edge means forcing it to reset in a shorter period, and means for differentiating the trailing edge of the delay flop signal to said pinch roll.

Claim 6

In a data recording machine of the character described, a tape short circuit comprising read amplifiers for receiving signals produced when a ''''1'''' bit is sensed on tape, a first two input ''''AND'''' gate, signalling means operable when the machine is conditioned to read tape to provide a true signal to one input of said ''''AND'''' gate, the other input of said gate being connected to said amplifiers whereby the gate is made active when information is read from tape, a two input ''''OR'''' gate one input of which is connected to the output of said first ''''AND'''' gate, a first delay device connected to the output of said ''''OR'''' gate, said delay device producing tape sprockets at its output in response to signals received from said ''''OR'''' gate, a second delay device connected to the output of said first delay device, said second delay device being operable to generate a signal if said first delay device has not produced a tape sprocket after a fixed period of time, and a second two input ''''AND'''' gate, said tape read signal means being operable to provide a true signal to one input of said second ''''AND'''' gate, said second delay device being connected to the other input of said second ''''AND'''' gate, the output of said second ''''AND'''' gate being connected to the other input of said ''''OR'''' gate whereby the latter provides an artificial tape sprocket through said first delay device when said second ''''AND'''' gate becomes active.

Claim 7

In a data recording machine of the character described, a tape short circuit comprising read amplifiers for receiving signals produced when a ''''1'''' bit is sensed on tape, a first two input ''''AND'''' gate, signalling means operable when the machine is conditioned to read tape to provide a true signal to one input of said ''''AND'''' gate, the other input of said gate being connected to said amplifiers whereby the gate is made active when information is read from tape, a two input ''''OR'''' gate one input of which is connected to the output of said first ''''AND'''' gate, a first delay device connected to the output of said ''''OR'''' gate, said delay device producing tape sprockets at its output in response to signals received from said ''''OR'''' gate, a second delay device connected to the output of said first delay device, said second delay device being operable to generate a signal if said first delay device has not produced a tape sprocket after a fixed period of time, and a second two input ''''AND'''' gate, said tape read signal means being operable to provide a true signal to one input of said second ''''AND'''' gate, said second delay device being connected to the other input of said second ''''AND'''' gate, the output of said second ''''AND'''' gate being connected to the other input of said ''''OR'''' gate whereby the latter provides an artificial tape sprocket through said first delay device when said second ''''AND'''' gate becomes active.

Claim 8

A circuit as defined in claim 1 wherein the delay provided for by said second delay device is substantially longer than that provided for by said first delay device.

Claim 9

A circuit as defined in claim 4 wherein the delay of said first delay device is a nominal 80 microseconds and the delay of said second delay device is a nominal 900 microseconds.

Claim 10

A tape sprocket circuit as defined in claim 4 in combination with a timed drive circuit for supplying a control signal to the tape drive means, said timed drive circuit including a differentiator for differentiating the trailing edge of said control signal, said differentiator being operable to force a signal into read amplifiers whereby tape sprockets are produced by the tape sprocket circuit if said tape read signal means is applying a true signal to said first ''''AND'''' gate.

Claim 11

In a magnetic tape read system wherein a tape drive mechanism advances a tape past a station in response to a tape drive signal and wherein blocks of data on said tape are read during individual read cycles, each said cycle being determined by counting means arranged to count the number of characters read and to terminate the cycle after a predetermined number of characters have been read, the combination comprising: first circuit means for generating a tape sprocket signal a first predetermined time interval after the first bit of each character is sensed, said tape sprocket signals causing advancement of said counting means; timing means responsive to each said tape sprocket signal for initiating the timing of a second predetermined interval and for generating an output pulse at the termination of said second interval, said second interval being longer than the time between data characters in a normal read cycle; and second circuit means responsive to said output signal for generating additional tape sprocket signals, whereby the read cycle is terminated even through said predetermined number of characters is not included in a data block.

Claim 12

In a magnetic tape read system wherein a tape drive mechanism advances a tape past a station in response to a tape drive signal and wherein blocks of data on said tape are read during individual read cycles, each said cycle being determined by counting means arranged to count the number of characters read and to terminate the cycle after a predetermined number of characters have been read, the combination comprising: first circuit means for generating a tape sprocket signal a first predetermined time interval after the first bit of each character is sensed, said tape sprocket signals causing advancement of said counting means; timing means responsive to each said tape sprocket signal for initiating the timing of a second predetermined interval and for generating an output pulse at the termination of said second interval, said second interval being longer than the time between data characters in a normal read cycle; and second circuit means responsive to said output signal for generating additional tape sprocket signals, whereby the read cycle is terminated even through said predetermined number of characters is not included in a data block.

Claim 13

The system set forth in claim 8 further comprising: a one shot multivibrator operable to terminate said tape drive signal after a third predetermined time interval substantially longer than said second interval; and means responsive to termination of said drive signal for causing said first circuit means to generate a tape sprocket signal to actuate said timing means.