Method for determining an offset value for a gain of a transmission path, transmission path with adjustable gain, and use of the transmission path

A method for determining an offset value for a gain of a transmission path, comprising:

• providing a transmission path having an adjustable total gain;
• setting an initial total gain of the transmission path by setting a first gain and setting a second gain associated with the transmission path;
• supplying a first test signal to the transmission path and ascertaining a level of a first output signal from the transmission path;
• altering the second gain by at least one value, and altering the first gain so that the total gain of the transmission path remains substantially the same as the initial total gain;
• supplying a second test signal to the transmission path and ascertaining a level of a second output signal from the transmission path;
• and
• determining an offset value for the second gain by comparing the ascertained levels of the first and second output signals.

A transmission path having an adjustable gain, comprising:

• a signal input;
• a control input configured to set a gain of the transmission path:
• a baseband unit connected to the signal input, the baseband unit comprising a first discrete-value adjustable amplifier having a control input for setting a gain thereof;
• a second discrete-value adjustable amplifier having a control input for setting a gain thereof, the second discrete-value adjustable amplifier having an input coupled to an output of the baseband unit;
• a control unit having a correction input, and a nominal input coupled to the control input of the transmission path, wherein the control unit is configured to output a first gain control signal to the control input of the first amplifier and a second gain control signal to the control input of the second amplifier, wherein at least the first gain control signal is derived from a discrete-value nominal signal at the nominal input and from a correction signal at the correction input;
• and
• a correction unit configured to output the correction signal to the correction input of the control unit to compensate for an offset in the gain of the first or second amplifiers, or both.