In this short application document we show how the Frame Sync Output signal looks in an oscilloscope and how you can verify this signal if you need to corroborate its characteristics. The camera used for this test is a Chronos 1.4 camera, it is built on the same architecture as the Chronos 2.1-HD so there is no difference in the output provided, in case you own a Chronos 2.1-HD.
Frame Sync Output. This is a signal whose features are defined by the frame rate and the exposure time the camera is recording at.
When a user selects frame rate and exposure time from the camera that is what the Frame Sync Output signal provides.
When the camera is run by an external device the Frame Sync Output signal outputs the features of the external signal provided to the camera.
In figure 1 you can see the parameters entered in the Record Settings screen. Frame rate is 1000 fps and exposure time is 900 µs.
The maximum frame rate at full resolution for this camera is 1069 fps, for simplicity 1000 fps is entered.
Figure 1. The parameters entered in the Record Settings screen.
Figure 2 displays the output of the signals around the time the camera is triggered. The camera is triggered with a trigger switch button. Next, the signal from the trigger switch button, yellow trace, and the camera’s Frame Sync Output signal, blue trace, are fed to an oscilloscope, Rigol DS1104 1 GSA/s.
Connections and settings:
Trigger signal
The trigger switch button is connected to the BNC input located on the side of the camera.
In the Trigger /IO Settings the IO 1 (BNC) is set to Record End Trigger.
Frame Sync Output signal
A phoenix connector, Phoenix Contact part number 1778890, and a BNC to Mini grabber test lead are attached to the side of the camera. The other end of it connected to the Oscilloscope.
In the Trigger /IO Settings the IO 2 is set to Frame Sync Output.
In figure 2 each horizontal division is 200 µs. The trigger signal appears a few hundred µs before the camera begins to record. The camera only records when the next rise of the blue trace appears. Thus when the camera records the blue trace is in a high state, 4.28V.
The red line with the text Exposure time is the time the camera is recording one frame. Note the red rectangle on the right side that the distance, in time, between the two cursors is 900 µs, which is the exposure time entered in the Record Settings screen.
At the lower left section, the period of the signal in Channel 2 is 1 ms. This is in agreement with the interfame, as the frame rate the camera was set to is 1,000 fps.
Figure 2. Output signals from the camera showing the exposure time
Finally, in the last image, figure 3, the interframe is displayed. The distance between the cursors is 1.0 ms. Notice that there is a short time, 100 µs when the camera is not recording.
The exposure time cannot be the same as the interframe time, regardless of the frame rate used or resolution. This is because the camera needs a finite amount of time to download the recorded data in the sensor.
Figure 3. Output signals from the camera showing the interframe time.
The Frame Sync Output signal can be useful in the following applications
Experimental settings
Process monitoring
Camera synchronization with other cameras
Camera synchronization with other devices