The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 19, 1988
Filed:
Jul. 30, 1987
Colin K Howley, Stonehouse, GB;
Renishaw plc, Wotton-under-Edge, GB;
Abstract
A frequency-to-voltage converter, as applied to controlling the speed of a motor, comprises: a motor speed encoder (1) producing first and second alternating signals (3a,3b) each at the same, first frequency which frequency is dependent on the said speed, the first and second signals being in quadrature with each other; a reference oscillator (4), for producing third and fourth alternating signals (5a,5b) each at the same, reference frequency, which frequency is higher than said first frequency, the third and fourth signals being in quadrature with each other; and single sideband modulating means (6,7,8) connected to receive the first, second, third and fourth signals and to produce a fifth alternating signal (8a) which is a frequency-shifted version of one of the first and second signals. The fifth signal and one of the third and fourth signals (5b) are applied to respective frequency-to-voltage converters (9,10), the DC output voltages of which are subtracted from each other in a differential amplifier (12). The DC output voltage of the amplifier is proportional to the speed of the motor and is used to control the speed to a desired value. The converter provides a DC signal inherently free from ripple over a wide dynamic range.