Gte Automatic Electric Labs Inc.

Gte Automatic Electric (canada) Limited

Stanley R Norman

Kam B Tin

An access circuit for use in a computer input-output channel. Retriggerable mono-stable multivibrators are used to provide access timing periods during which an input-output device can access a computer channel to the exclusion of other input-output devices.

Computer channel access circuit for multiple input-output devices

A noise eliminator circuit for use in a decoding circuit. A flip-flop is used to delay a first pulse train by the pulse width of a second pulse train so that pulse level transitions of the first pulse train occur non-coincident with the pulse level transitions of a synchronously generated third pulse train.

Noise eliminator circuit

A noise detecting circuit for a data processing channel operates on incoming noise pulses and trains of data pulses, each train of which is preceded by a start pulse of a duration substantially greater than the characteristic duration of a noise pulse. The noise detecting circuit generates a noise verification pulse in response to a first incoming pulse after a predetermined interval of time following the receipt of the first incoming pulse, which interval is greater than the characteristic duration of a noise pulse and less than the duration of a start pulse. Consequently, there is time coincidence between the noise verification pulse and the first incoming pulse if the first incoming pulse is a start pulse but there is no time coincidence between the noise verification pulse and the first incoming pulse if the first incoming pulse is a noise pulse. Means are included for detecting such non-coincidence and for generating an inhibit signal to indicate that the first incoming pulse is a noise pulse and to inhibit a data processing channel from processing the next incoming pulse.

Noise detecting circuit

A control device is described for linking a motor operated data terminal to a data processor which provides information signals including data characters and data terminal motor-start signals. The motor associated with the data terminal is selectively operable between an on condition and an off condition and is programmed to switch from the on condition to the off condition after a first predetermined interval following the last reception of data characters from the data processor. The data terminal motor switches to the on condition upon receipt of a data terminal motor-start signal and reaches its normal operating speed in at least a second predetermined interval after the receipt of a data terminal motor-start signal. The control device includes means for receiving the information signals from the data processor and for transmitting such signals to the data terminal. A first circuit of the control device is responsive to received information signals from the data processor for providing a motor-on status signal to the data processor and is responsive to the absence of information signals for the first predetermined interval for providing to the data processor a motor-off signal. A second circuit of the control device senses the receipt of a motor-start signal from the data processor for providing the data processor with a data terminal busy condition signal of a second predetermined interval. Following the expiration of the second predetermined interval, a terminal non-busy signal is provided to indicate to the data processor that data characters may be sent. Accordingly, upon interruption of transmission of data characters by the data processor for an interval of time equal to the first predetermined interval, the data processor is provided by the control device with a motor-off signal to indicate that a motor-start signal must be sent prior to further transmission of data characters. Upon transmission of a motor-start signal, the data processor is provided with a motor-on signal and a terminal busy condition signal. The terminal busy condition signal further inhibits transmission of data characters for the second predetermined interval until a terminal non-busy condition signal is provided.

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Brockville, Canada

Stanley R Norman