Variable gain amplifier
US6509798B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jun 22, 2001 |
| Grant date | Jan 21, 2003 |
| Priority date | — |
| Expiry date | Jun 22, 2021 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03G1/0023
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
The variable gain amplifier includes a parallel connection of resistance R2 and capacitor C2. Resistance R2 may be replaced by inductance L, and bipolar transistors may be replaced by other types such MOS transistors. Resistance R2 gives a current feedback for transistor Q2, thereby lowering the mutual conductance “gm” of transistor Q2, and limiting the current flowing from voltage supply V0. The emitter area ratio (the emitter area of transistor Q2: the emitter area of Q3) made to be 1: n where “n” is greater than or equal to 1, thereby controlling each current. Capacitor C2 is connected in parallel with R2 connected with the base of transistor Q2 is a bypass capacitor for lowering the impedance of the base of transistor Q2 in higher frequency range. Capacitor C2 is a peaking capacitor, because it improves the high frequency characteristics.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.