Hardware Reference
In-Depth Information
Figure 11.19
Simultaneous time domain and frequency domain displays
provided by Software Oscilloscope
approximately 600 Hz). Figure 11.20 shows a modulated waveform displayed
using Windows Oscilloscope 2.51. The waveform consists of a sine wave at
440 Hz modulated at 100 Hz to a depth of about 25%.
A video cross-hatch waveform (vertical scan) displayed using Windows
Oscilloscope 2.51 is shown in Figure 11.21. Note that the sweep time has
been set to 36 ms and, as a consequence, 1.8 (i.e. 36/20) cycles of the 50 Hz
vertical scan waveform are displayed. The signal amplitude is approximately
1.3 V peak-peak. A vertical scan video colour bar waveform is shown in
Figure 11.22. Note that the absolute DC level cannot be correctly shown due to
the AC coupling used in the sound card input interface.
Figure 11.23 shows an expanded view of the vertical sync pulse shown in
Figure 11.22. To obtain this waveform the timebase has been set to produce a
horizontal sweep time of 5.4 ms. Notice that it is just possible to distinguish
individual line scans in Figure 11.23.
