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:
Nov. 13, 1984
Filed:
Apr. 13, 1982
Hitoshi Hirata, Tokyo, JP;
Pioneer Electronic Corporation, Tokyo, JP;
Abstract
A PLL detection circuit for use in an AM-PM type AM stereo receiver in which unwanted AC signal components included in the output of a phase comparator are suppressed by switching the frequency response characteristic of a loop filter in the PLL detection circuit as locking is reached so that only the DC signal component, corresponding to the phase difference of the input signal and a reference signal, is outputted. A changeover circuit, including a switching circuit composed of a pair of parallel-connected transistors, is connected in parallel with an element of the loop filter, the component value of which affects or is at least partially determinative of the frequency response characteristic of the loop filter. The changeover circuit is activated by a control signal indicative of the locking state of the PLL detection circuit.