Max Henry Behrens

US Patent:

51755084, Dec 29, 1992

Filed:

Dec 5, 1991

Appl. No.:

7/802686

Inventors:

Randal R. Gingrich - Belleville MI
Nicholas L. Difiore - Farmington Hills MI
Max H. Behrens - Plymouth MI

Assignee:

Ford Motor Company - Dearborn MI

International Classification:

H03F 308
H03G 320

US Classification:

330 84

Abstract:

A voltage-controlled amplifier employs an operational amplifier with negative feedback for setting the gain. A voltage variable resistance such as a junction-field-effect transistor (JFET) is employed as part of a variable voltage divider for controlling the amplifier gain. Resistors in series and in parallel with the JFET determine minimum and maximum resistances corresponding to upper and lower limits for the amplifier gain. Thus, multiple channels of an amplifier can be provided with closely matched characteristics even using separate JFETs in each separate channel which have unmatched characteristics.