Fast single-ended to differential converter

摘要

A single ended to a differential signal converter. The single ended signal is passed through a high pass filter to block DC components. A positive and a negative version of the filtered signal are used collectively as the differential output of the converter. To allow accurate measurements on the input signal without waiting for the output of the high pass filter to settle, the differential outputs are offset by a dynamically generated signal representative of the midpoint of the filtered signal. That offset is generated by capturing a value representing the midpoint when a signal is first applied. This captured value is allowed to change with a time constant matching a time constant of the high pass filter. The converter may be used to connect a test instrument to a unit under test that generates test signals in a format that the test instrument is not specifically configured to measure.

主权项

1. A converter adapted to convert a single-ended input signal at a single-ended input to an output signal at an output, the converter comprising:
a first circuit comprising a first input and a first output, the first input being coupled to the single-ended input to receive the single-ended input signal, the single-ended input signal having a first time constant and a midpoint, wherein the first circuit is configured to:
capture, from an edge of the single-ended input signal, a value representative of the midpoint of the single-ended input signal at the first input;generate, from the value captured from the edge of the single-ended input signal, a decaying signal having a second time constant representative of the first time constant of the single-ended input signal; andprovide the decaying signal at the first output.