Dc offset compensation

A conversion circuit comprising:

• a voltage controlled oscillator (VCO) configured to sequentially provide a first VCO output signal based on a first signal for a first period and a second VCO output signal based on a second signal for a second period;
• and
• a counter configured to count pulses in the first VCO output signal and the second VCO output signal and generate a difference count value of the difference in the number of pulses in the first VCO output signal during said first period and the number of pulses in the second VCO output signal during said second period.

An apparatus comprising:

• a controlled oscillator having an input cyclically multiplexed between a first signal for a first period and a second signal for a second period and to generate an oscillation signal with a frequency controlled by said first or second signal;
• and
• a counter configured to count oscillations in the oscillation signal and determine a difference in the number of oscillations during said first period and said second period.