Patent ID: 9568581
Date: 2017-02-14
CPC Classifications: G01R

Claim:
1. A circuit configured to sample a signal of a source circuit and to provide calibration signals to a testing device of the signal sampled from the source circuit, the circuit comprising: an amplifier configured to drive signals on an internal node to the testing device; a sampling circuit configured to provide a sample of the signal from the source circuit to the internal node; and a calibration circuit configured to provide both a first calibration voltage and a second calibration voltage to the internal node for calibration of the testing device with respect to the sample of the signal, wherein the second calibration voltage is different from and a constant known proportion of the first calibration voltage, and the second calibration voltage is derived from the first calibration voltage using a voltage divider circuit such that the first calibration voltage and the second calibration voltage always have the same polarity.