US4078193A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Capstan speed control system
Assignee: Unisys Corp
•
Filing: 1976-04-21
•
Granted: 1978-03-07
•
Expires: 1996-04-21
Abstract
Abstract A magnetic tape-transport system wherein the speed of a capstan used to transport magnetic tape past a read-write head is controlled utilizing digital techniques. A comparator is provided a first digital input indicative of desired speed and a second input from a counter which counts up or down until the count equals the first digital input. The counter output is converted to an analog voltage and applied to a summing junction point which also receives a voltage which is proportional to the instantaneous speed of the capstan drive motor. The voltage difference at the summing junction point is used to drive the capstan drive motor.
Inventors
- 👤 David Robert Anderson
- 👤 Vaughn Junior Jenkins
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 19:53
CPC Classifications
G; G11; G11B; G11B15/00; G11B15/18; G11B15/44; G11B15/46; G11B15/48; G11B15/54; Y; Y10; Y10S; Y10S388/00; Y10S388/90; Y10S388/902; Y10S388/907; Y10S388/912
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
287 words
A tape-transport system having a capstan for transporting tape past a read-write head, comprising in combination: a motor connected to the capstan for driving the capstan in a first or second direction; control means providing speed and direction command signals; generator means connected to the output of said control means and responsive to said speed and direction commands from said control means to provide a digital output indicative of the desired speed and direction of the capstan; a digital comparator connected at one input to the output of said generator means for receiving said digital output therefrom; an up-down counter; a clock-pulse source connected to said up-down counter to cause said up-down counter to count in synchronism with the occurrence of clock pulses from said source; a digital-to-analog converter connected to the output of said up-down counter for continuously converting the output count of said counter to an analog voltage; conductor means coupling the output of said counter back to another input of said digital comparator; said digital comparator for comparing the digital outputs from said generator means and said counter and connected at an output to said counter for providing a signal to cause said counter to change its count until its digital count equals the digital output from said generator means; tachometer generator means connected to said motor for providing an output voltage proportional to the instantaneous velocity of said motor and having a polarity opposite to that of said analog voltage; and summing junction means connected to said converter and said tachometer generator means for summing the output voltages therefrom and connected to said motor whereby said motor receives a drive voltage only when the tachometer voltage and said analog voltage differ in amplitude.
Claim 2
Dependent Claim
287 words
A tape-transport system having a capstan for transporting tape past a read-write head, comprising in combination: a motor connected to the capstan for driving the capstan in a first or second direction; control means providing speed and direction command signals; generator means connected to the output of said control means and responsive to said speed and direction commands from said control means to provide a digital output indicative of the desired speed and direction of the capstan; a digital comparator connected at one input to the output of said generator means for receiving said digital output therefrom; an up-down counter; a clock-pulse source connected to said up-down counter to cause said up-down counter to count in synchronism with the occurrence of clock pulses from said source; a digital-to-analog converter connected to the output of said up-down counter for continuously converting the output count of said counter to an analog voltage; conductor means coupling the output of said counter back to another input of said digital comparator; said digital comparator for comparing the digital outputs from said generator means and said counter and connected at an output to said counter for providing a signal to cause said counter to change its count until its digital count equals the digital output from said generator means; tachometer generator means connected to said motor for providing an output voltage proportional to the instantaneous velocity of said motor and having a polarity opposite to that of said analog voltage; and summing junction means connected to said converter and said tachometer generator means for summing the output voltages therefrom and connected to said motor whereby said motor receives a drive voltage only when the tachometer voltage and said analog voltage differ in amplitude.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-03-06 | 1981-09-05 | 1982-03-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-03-06 | 1985-09-05 | 1986-03-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-03-06 | 1989-09-05 | 1990-03-07 | $7700.00 | Window Closed / Lapsed |