System object: visionhdl.MeasureTiming
Measure timing of pixel control structure input
Alternatively, instead of using the
to perform the operation defined by the System object™, you can
call the object with arguments, as if it were a function. For example,
= step(obj,x) and
y = obj(x) perform
= step(measure,ctrlIn) incorporates the current pixel location
into calculations of video frame timing. The control signals,
associated with each pixel indicate the location of this pixel relative
to the active frame boundaries. The input object measures the time
steps between the control signals to determine the parameters of each
The System object performs an initialization the first time
you call the
step method. This initialization locks
nontunable properties and input specifications, such as dimensions,
complexity, and data type of the input data. If you change a nontunable
property or an input specification, the object issues an error. To
change nontunable properties or inputs, first call the
to unlock the object.
measure— Timing analyzer
visionhdl.MeasureTiming System object that
you created and configured.
The diagram shows the output measurements, as determined from the pixel stream control signals.
For details on the pixel control bus and the dimensions of a video frame, see Streaming Pixel Interface.
Measurements from the first simulated frame are incorrect because some parameters require measurements between frames. Simulate at least two frames before using the results.
activePixels— Number of active pixels per line
This value is measured between
1 in the diagram.
activeLines— Number of active lines in the frame
This value is measured as the number of
2 in the diagram.
totalPixels— Number of pixels in the line
This value is measured from
hStart to the
hStart, including the horizontal blanking
interval. See marker
3 in the diagram.
totalLines— Number of lines in the frame
This value is measured by the interval from
vEnd, divided by
It includes the vertical blanking interval. See marker
horizBlank— Number of pixels in the horizontal blanking interval
The horizontal blanking interval is the number of inactive pixels
between lines of a frame. This value is measured between
hStart. See marker
vertBlank— Number of lines in the vertical blanking interval
The vertical blanking interval is the number of inactive lines
between frames. This value is measured from
vStart, adjusted to remove
then divided by
totalPixels. See marker