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. 06, 2012
Filed:
May. 30, 2011
Tzyy-sheng Horng, Kaohsiung, TW;
Chieh-hsun Hsiao, Kaohsiung, TW;
Kang-chun Peng, Kaohsiung, TW;
National Sun Yat-Sen University, Gushan District, Kaohsiung, TW;
Abstract
A direct-conversion transmitter with resistance to local oscillator pulling effect comprises a local oscillation circuit, a quadrature modulator connected with the local oscillation circuit, a power amplifier connected with the quadrature modulator, a first variable analog delay device connected with the power amplifier, a variable analog attenuator connected with the first variable analog delay device, an inner self-injection loop, and a power combiner connected with the variable analog attenuator and the inner self-injection loop. The local oscillation circuit comprises a two point voltage-controlled oscillator and a phase locked loop connected with the two point voltage-controlled oscillator. The inner self-injection loop comprises a second variable analog delay device, a phase shifter connected with the second variable analog delay device and a variable gain amplifier connected with the phase shifter. Signal distortion due to pulling effect in direct-conversion transmitter can be effectively suppressed by circuit design over the inner self-injection loop.