Invention Grant
- Patent Title: Method for reducing IM2 noise in a down conversion circuit
- Patent Title (中): 降低转换电路中IM2噪声的方法
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Application No.: US10531231Application Date: 2003-10-15
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Publication No.: US07263344B2Publication Date: 2007-08-28
- Inventor: Tajinder Manku
- Applicant: Tajinder Manku
- Applicant Address: CA Waterloo, Ontario
- Assignee: Sirific Wireless Corporation
- Current Assignee: Sirific Wireless Corporation
- Current Assignee Address: CA Waterloo, Ontario
- Agency: Borden Ladner Gervais LLP
- Agent Shin Hung
- International Application: PCT/CA03/01574 WO 20031015
- International Announcement: WO2004/036776 WO 20040429
- Main IPC: H04B1/26
- IPC: H04B1/26

Abstract:
The present invention relates generally to communications, and more specifically to a method and apparatus for minimizing DC offset and second-order modulation products (IM2 noise) while demodulating RF signals. The principle of the invention can be applied to differential, down-conversion circuits (50) consisting of two differential mixers (54, 56) in series, a follows: a pair of current sources Ia and Ib are used to provide current to positive and negative channels of the first differential mixer (54). Providing current to the amplifying transistors of the first mixer (54) reduces the current drawn through the active mixer switches, reducing the noise generated. The current sources 1a and 1b are trimmed in a complementary manner where 1a=I+Delta1, and 1b=Delta1. The value of Δ1 can be determined in a number of manners; for example, it could be established by testing after the circuit has been fabricated, and the value stored on-chip, for future use.
Public/Granted literature
- US20060148438A1 Dc trimming circuit for radio frequency (rf) down-conversion Public/Granted day:2006-07-06
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