A circuit configured to generate an analog signal having a pre-determined pattern. The circuit includes a plurality of digital-to-analog converters. Each of the plurality of digital-to-analog converters includes a plurality of current sources configured to generate a plurality of square waveforms and a summer configured to sum the plurality of square waveforms to generate the analog signal having the pre-determined pattern. Each square waveform is delayed by a pre-determined amount delay relative to another square waveform of the plurality of square waveforms. The pre-determined amount of delay between each square waveform of the plurality of waveforms is adjustable to adjust the pre-determined pattern of the analog signal. The pre-determined amount of delay is non-uniform throughout the circuit.