Thread: Download RC-USB Joystick Files
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Old Apr 16, 2008, 12:12 PM
Andy64 is offline
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Hillsboro, OR
Joined Aug 2007
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DX7 Signals

I just took a look at the output of my DX7. Its PPM and about 22mS cycle time.

However, its only about 1.4 Vpp and apparently AC coupled. With the DX7 output connected to the direct coupled scope (10 Meg impedance) the signal goes between +.4 and -1.0 V. The levels are determined by the duty cycle of the signal. That probably explains why it could work for a few seconds (while the coupling cap gets charged) then quit.

I believe the input circuit will need to be revised. A simple diode (Schottky?) clamp might be a solution.
The PIC and XTAL for my NG2 should arrive today so I should be able to take a closer look.

Can anyone comment on whether or not the 22mS time should be OK?
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