Arbitrary Chirping

The DSM303 can not only output linear chirping but also arbitrary chirping where the frequencies can be anything the user wants. This can be done using either the GUI or API using special user waveform files. With arbitrary chirping users can generate linear, exponential and even random chirps.

Shown below is an actual linear chirp from the DSM303 as captured from an oscilloscope. The waveform consists of four segments that repeat back to to back. For each segment of the waveform, the module chirps from ¹/₂₅₆ of the input clock frequency all the way up to ¹/₁₆ of the input clock frequency in steps of ¹/₂₅₆ of the input clock frequency. The frequency update rate is ¹/₈ of the input clock frequency . In our example we used a 2.0 GHz clock so for each segment, the module is chirping from 7.8125 MHz ( 2000 / 256 ) all the way up to 125 MHz ( 2000 / 16 ) in steps of 7.8125 MHz. The frequency update rate is 250 MHz ( 2000 / 8 ). The total waveform length is about 256 ns.

Here is a graphical representation of the above waveform. The 0 frequencies at the beginning denotes that the module is in reset mode to set the phase to 0. The chirping does not start until point 12.

For more information on the DSM303, please click here.