[sdiy] Digital control

[Peter Ullrich]

> > I'm thinking about building some simple analog FX modules, mainly a
> > compressor and a filter. However, I would really like digital control
> > over them; at least patch memory. What's the simplest/cheapest way of
> > implementing this? I have some experience with PIC programming, so I
> > guess what I need help on are some digitally controlled resistors or
> > something, to replace the pots.

Maybe not the cheapest part but nice for Audio purposes with fine resolution 
are the ML2003 and ML2004 by Micro Linear and Fairchild:

General Description
The ML2003 and ML2004 are digitally controlled logarith-mic
gain/attenuators with a range of –24 to +24 dB in 0.1 dB
steps.
The gain settings are selected by a 9-bit digital word.
The ML2003 digital interface is either parallel or serial.
The ML2004 is packaged in a 14-pin DIP with a serial
interface only.

Features
• Low noise: 0 dBrnc max with +24dB gain
• Low harmonic distortion: -60dB max
• Gain range: –24 to +24dB
• Resolution: 0.1dB steps
• Flat frequency response:
	±0.05dB from .3–4 kHz
	±0.10dB from .1-20 kHz
• Low supply current 4mA max from ±5V supplies
• TTL/CMOS compatible digital interface
• ML2003 has pin selectable serial or parallel interface;
  ML2004 serial interface only


Ciao
Peter

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                               Ing. Peter Ullrich   
	               Hardware & Software Developer  /  Electronic Musician
                               Private Homepage: http://www.ullrich.at.tt
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