Patent ID: 6876257

Claim:
A gain control circuit comprising: a control voltage supply circuit using an external control voltage to generate an internal control voltage, said internal control voltage relative to said external control voltage from a first reference voltage to a second reference voltage being different from when said external control voltage is less than said first reference voltage or exceeds said second reference voltage; and a variable gain circuit having an uncompensated gain characteristic and a compensated gain characteristic, said uncompensated gain characteristic relative to said external control voltage being linear from said first reference voltage to said second reference voltage, and being non-linear when said external control voltage is less than said first reference voltage or exceeds said second reference voltage, said variable gain circuit using said internal control voltage to produce a compensated gain characteristic, and said compensated gain characteristic relative to said external control voltage being linear from said first reference voltage to said second reference voltage, and being linear when said external control voltage is less than said first reference voltage or exceeds said second reference voltage, wherein said compensated gain characteristic is a transmission gain.