Re: Write Signal on Disk II Question



I think you are thinking that more data can be encoded than is done with the present scheme. It might be an interesting achedemic exercise and if I were you, I'd study the QAM modulation schemes often used in broadband communications. However keep in mind that there is only 1 write output control to this drive, there is very limited bandwidth on a floppy interface and a relatively low signal to noise ratio, so you are very limited to what can be achieved.

see http://en.wikipedia.org/wiki/Quadrature_amplitude_modulation

Regards,
Mike Willegal

Bryan Parkoff wrote:
Mike,


The field being generated is never absent when writing, it is changed in polarity for each one bit. This is not a digital (on or off) signal.


I understand. It is easy to create data array to hold digital binary like digital_binary[100000] variable. It may be possible to create analog_binary[100000] variable. The analog_binary[100000] variable uses real number instead of integer number. The real number can tell how much voltage in positive polarity, negative polanity and perhaps absence of polarity. I am curious to see if it can be done in simulation to draw analog clock cycle.
We know that we can be able to write more than two adjusted ZERO bits without any problem. The Read Sequencer in the logic state sequencer ROM is designed to read only one or two adjusted ZERO bits maximum. It could be possible to read three or more adjusted ZERO bits reliably if you redesign to modify state sequencer. It may be 32 or 64 state sequencer instead of 16 state sequencer.
It is the reason why I am saying because I want to record all presence of read pulse and absence of read pulse into RAM. Maybe, special controller card is capable of recording all instead of Disk II controller card. What do you think?
Is it true that copy-protected NIB image is less successful (like spiral scheme) to run on Apple II Emulator? It is possible that all copy-protected images work on Apple II Emulator if recorded read pulses are used.

Bryan Parkoff


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