[sdiy] Logic Gate help (Help!)

[Oren Leavitt]

On 1/26/2013 5:42 PM, Donald Tillman wrote:
>
> On Jan 26, 2013, at 10:40 AM, cheater cheater <cheater00 at gmail.com> wrote:
>
>> What I'm asking is whether their use of RTL is an implementation
>> detail that might be executed differently nowadays (CMOS, FPGA), or if
>> it simply is the best way to do what they are doing, even today.
>
>
> Fine question.  Does anybody know what year the Moog 960 came out?  It may have been the first Moog module to use IC's.
>
> You can get a feel for the technology of the time by going back through old issues of Popular Electronics Magazine.  Here's one source, I'm sure there are better ones:
>
>     http://www.swtpc.com/mholley/PopularElectronics/Popular_Electronics.htm
>
> If the Moog 960 was designed around 1969, the available logic families were probably RTL, ECL, DTL, TTL, and Signetics' "Utilogic" (there's a blast from the past).  The last three were pretty much the same, and certainly compatible.  And, of course, individual diodes and transistors.
>
> RTL was very well suited for this:
>     * inexpensive
>     * more functions available
>     * handled a wide range of supply voltages
>     * well behaved
>     * you could wire-NOR the outputs
>     * interfaced to linear circuitry nicely
>     * could be biased into linear mode with a resistor
>
> So RTL is the most like CMOS, but still different.  I'm sure the Moog 960 took advantage of some of those features, so a blind substitution probably wouldn't work.
>
> I built my first sequencer in 1971 when I was 14 years old (I think), so I remember these issues well.
>
>    -- Don
>
> --
> Don Tillman
> Palo Alto, California
> don at till.com
> http://www.till.com
>

Yeah, the 960 used 1960's era 700/900 series RTL ICs and a voltage 
controlled UJT oscillator similar to that of the 901 VCO. It is a 
clocked shift register (instead of a counter/decoder) that lets you set 
the start point and skip steps.
I would think a modern implementation could be done simpler with the 
bigger choice of IC building blocks these days.
The Synthesizers.com Q960 is a modern remake of the Moog 960. I think 
Roger uses standard CMOS in his version.

- Oren