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:
Sep. 26, 1989
Filed:
Apr. 08, 1988
Ahmed M Said, Beaverton, OR (US);
Tektronix, Inc., Beaverton, OR (US);
Abstract
Methods and circuits for implementing them determine the phase angle of a complex electrical signal from the in-phase and quadrature components of the signal by truncating the magnitudes of the real and imaginary components of the signal and combining them to form an address which is then used to access a lookup table containing angular values. However, if both of the values are small, before they are truncated they are both expressed in terms of a lowest common exponent, i.e., shifted left as much as possible without affecting their ratio. The phase angle from -180 to +180 degrees may be found directly from the lookup table, or, in an alternative variation on the method, a single-quadrant angle is looked up in a shorter table and then supplemented according to quadrant information contained in the signs of the values to produce the total phase angle. Circuits are disclosed for implementing both methods for inputs in 2's complement or sign and magnitude form.