The command format for my DDS board sends the ASCII Hex characters for
accumulator N value, and so the values to be sent depend on the DDS clock
frequency which can have any arbitrary value. A high level control
programme for this board would normally first read the clock frequency
stored in EEPROM, then calculate the value to be sent for required output
frequency. This procedure means any driver programme can use any DDS
module, from one clocked at 4.194304MHz for LF all the way to a 180MHz
clocked unit for HF through UHF use. So generating a custom output from
the Jason S/W would need a two way interrogation process to read the clock
frequency, then calculate the values needed and format the Ascii hex
characters.
I was just going to use the generic Jason serial output, just the 8 bit
words taking on values 0 - 16 at 9600 baud. The PIC would calculate the
accumulator value for each tone by multiplying the received number by a
constant derived from the stored clock, then adding on the requested cenre
frequency.
Question... Is the nominal frequency of a Jason transmission the centre
frequency (Tone 8 ), or Tone 0 ? My understanding is the former, the centre
tone. But just checking.
Andy G4JNT
should you need modifications to the serial output format of Jason, just
ask.
V 0.94 has an additional format, optionally selectable, asked for by
Murray Greenman ZL1BPU for his AVR Atmel board.
I could as well produce an ad-hoc format for your board. If you need
details about the ZL1BPU format please contact me, but it is very simple.
73 Alberto I2PHD
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