PPM data streams
Posted: Thu 26 Feb 26 2009 10:30 am
The attached file is the scope trace of the PPM data stream from the JR9XII (equivalent to the JR9303). The trace is taken relative to the shield line from the D.S.C. port behind the radio. The vertical recticle is 500mV, and the horizontal recticle is 2.0ms.
Daniel
You will notice that the voltages are not centered around 0V, indicative that the output line probably passes through a large valued capacitor (AC-coupled). This could present problems for devices expecting a TTL compatible ground relative (DC-coupled) signal.
The frame time is precisely 22.0ms with 9-channels represented in the PPM frame. For this model at least, it does not appear that you can change the number of channels represented in the PPM frame. It's fixed at 9-channels.Daniel