21-02-2017, 10:46 PM
The twin DAC and analogue interpolator idea was used in the Pineapple converter. I've probably got the schematic somewhere.
If you're going to use programmable logic why not go the whole hog and get a FPGA prototyping kit. I think there are some pretty inexpensive ones around. Then you've got loads of logic to play with, including block RAM (or its Altera equivalent) to make line stores. Presumably you're already programming the CPLD in VHDL or Verilog so you've overcome that hurdle.
A 50:50 interpolator is pretty simple, just an adder and a bit of multiplexing. It's vastly better than no interpolator at all but not as good as a proper 2 line interpolator.
If you're going to use programmable logic why not go the whole hog and get a FPGA prototyping kit. I think there are some pretty inexpensive ones around. Then you've got loads of logic to play with, including block RAM (or its Altera equivalent) to make line stores. Presumably you're already programming the CPLD in VHDL or Verilog so you've overcome that hurdle.
A 50:50 interpolator is pretty simple, just an adder and a bit of multiplexing. It's vastly better than no interpolator at all but not as good as a proper 2 line interpolator.
www.borinsky.co.uk Jeffrey Borinsky www.becg.tv
