A SpectrumTrace message contains the spectrum trace data distributed by a CSM-Spectrum-Analyzer device. The spectrum trace is much like a read-only parameter (it may not be commanded to the M&C), instead of a single value it carries an array of numeric values.
The array elements represent the spectrum trace, all elements are integer numbers describing the point position in pixels from the top of the display downwards. The length of the trace depends on the particular spectrum analyzer model, common trace lengths are 501 or 601 points. The first array element is the leftmost point (at centerFrequency-frequencySpan/2), the last array element is the is the rightmost point (at centerFrequency+frequencySpan/2).
The point positions in the array (array index, element value) refer to the native size of the spectrum analyzer display as read out by the driver. This spectrum display size in pixels may be read from the spectrum analyzer device as the 'info.screen' variable. The spectrum analyzer widget on the screen may however re-scale the display to any size requested.
Data Model (extends Message)
| Key | Type | Value |
|---|---|---|
| id | String | The message ID (see Message) |
| type | String | The message type (always SPECTRUM, see Message). |
| time | String | Timestamp in format 'YYYY-MM-DDTHH:MM.SSZ', see Message). |
| trace | Array of Number | The spectrum trace, as an array of integer values, describing the point position in pixels from the top of the display downwards. |