USBee DX Mixed Signal Oscilloscope, Logic Analyzer and Bus Analyzer
This section details the operation of the Pulse Width
Modulator application that comes with the USBee DX. The Pulse Width Modulator application creates
a Pulse Width Modulated output for all of the 16 digital lines on the USBee
DX.
Click OK to enter the application. Below you see the
application screen.
Each channel outputs a repeating waveform with a 1kHz
frequency. The period of the repeating
waveform is made up of a high duration followed by a low duration and has 256
steps. The length of the High duration
is the PWM value that is shown. The
length of the Low duration is 256 – the High duration.
You can create a simple analog output voltage by using a
series resistor and a capacitor to ground on each channel.
The above shows 2 outputs of the PWM Controller. Signal 1 shows the PWM value set to 31 (out
of 255) and Signal 0 shows the PWM value of 137. A value of 0 is all low, and a value of 255
is mostly high (one out of 256 is low).
PWM Controller Specifications
|
Digital Channels Controlled
|
16
|
|
Analog Channels Controlled
|
0
|
|
Resolution
|
256 steps
|
|
PWM Frequency
|
1.02kHz
|
|
Control Mechanism
|
Slider Switch
|
|
Channel Output
Drive Current
|
4mA
|
|
Output Low Level
|
< 0.8V
|
|
Output High Level
|
> 2.4V
|
| 
