I have been extremely interested in the experiments you have conducted regarding sending unmodulated pulse streams. Being a new pronto owner (1 week so far) who unfortunately has a Pace Digital Cable STB, I am willing to pursue a solution to this problem.
I was able to borrow a digital storage scope and have sampled the transmission from my pace remote. As Merv has observed it consists of packets of data, spaced by 24.26245ms. The first 8 packets appear to contain the data, the packet nine and onward is a repetition of the packet eight, for as long as the remote button is held down.
Unfortunately, I have not had any success hand-coding the unmodulated pulse patterns. Could you provide more detail on the experiments you have performed. Examples of the codes you have used and their resultant waveforms would be useful.
Is the hex code format identical to modulated signals, i.e. word two defines the clock frequency, and hence the pulse high time for a burst pair of 0001 0001? Are there any similar limitations as found with modulated signals (i.e a low time must be at least 2 carrier clock cycles)?
Although the pace remote uses 115kbaud, a logic high has a high time (LED On) of 1.74us followed by 6.94us of low (LED Off), a logic low is just 8.68us of low (LED Off). Have you been able to produce pulses this short in your experiments?
Also do you know the maximum frequency the hex code can be encoded at. According to the formulae, an N = 1 should give a frequency of 4.145146MHz. Can this actually be used?
