An apparatus and method are provided for controlling a delay circuit. Included is a delay circuit configured to receive a probe signal. Further provided is a controller in electrical communication with the delay circuit. The controller is configured to perform various operations, in response to the receipt of the probe signal by the delay circuit. A positive peak and a negative peak of an output of the delay circuit are measured. Further, a ratio involving the positive peak and the negative peak of the output of the delay circuit is calculated. A delay of the delay circuit is controlled, based on the ratio.