User Guide (Version 2.2) of the
SiRad Simple® Evaluation Kit
- 15 -
3.2.3.1 Triggering measurements
You can choose between the two triggering modes ‘Self-triggering’ and ‘Manual triggering’. You can
find the steps to set them in Table 2.
Table 2: Triggering modes
Self-triggering (internal)
Manual (external) triggering
1. choose ‘Self-trigger’
1. choose ‘Manual trigger’
2. disable ‘Pre-trigger’
2. optionally enable ‘Pre-trigger’
3. optionally set a ‘Trigger delay’
3. manually send triggers on the
external trigger line (TR) - also see
Section 3.2.3.1 - or by sending
command frames (see the Protocol
Description)
Self-trigger:
activates the continuous measurement mode (default). The sensor triggers itself
repeatedly for continuous measurements.
Manual trigger:
deactivates the continuous measurement mode for manual external triggering. Use
this setting for asynchronous triggering or synchronized measurements between multiple radar
sensors. The sensor enters a low power mode after the transmission of measurement results and
wakes up upon the next trigger. Also see the Protocol Description for manual trigger commands.
Pre-trigger:
can be used to synchronize measurements between multiple radar sensors. If selected,
and the sensor is not in self-trigger mode, the sensor expects two external trigger commands to
execute one measurement. The two triggers have to be sent with a maximum delay of about 40ms
or the second trigger is ignored. Also see the Protocol Description for the trigger commands.
Trigger delay:
sets a delay time between two measurements when in self-trigger mode.
3.2.3.2 Frame options
DC cancellation:
activates the DC offset compensation of the ADC data.
Range data:
activates the transmission of the distance data frames, which contain the distance
spectrum data in dB for each distance bin (magnitude of the complex FFT output).
CFAR data:
activates the transmission of the CFAR data frames, which contain the threshold of the
constant false alarm rate (CFAR) operator in dB for each distance bin. The CFAR operator is an
adaptive algorithm to derive detection threshold for targets against noise.
Phase data:
activates the transmission of the phase data frames, which contain the values of the
phase angles for each distance bin (argument of the complex FFT output).
Target list data:
activates the transmission of the target list data frames, which contain a list of
targets including a target number, distance to the target, and their magnitude in dB and their phase.
The speed field is reserved.
Status update data:
activates the transmission of the status data update frames after every
measurement. If deactivated, the status frame is only transmitted after the sensor settings changed.
The status frame contains the distance unit (default: mm), the current maximum range of the
sensor, the measurement accuracy of the current setting, the gain setting of the baseband amplifier
for the last measurement, the update rate of the sensor and the bandwidth of the frequency ramps
used in the current setup.
Extended mode:
activates the transmission of the extended data frames (raw data) instead of the
standard sensor data frames. Please be aware that the extended data frames are not supported by
the WebGUI. No data will be shown in the WebGUI as long as the extended data mode is enabled.
Please see the Protocol Description for more information about the ‘Extended mode’.