Great explaination Florian!


On Fri, Jun 19, 2009 at 12:25 PM, Florian
Anwander< fanwander@... > wrote:

>
>
> Hi Greg
>
>> I'm not sure I fully understand track & hold, so I thought I'd ask...
>>
>> I am thinking of using the t&h module with a clock divider and a
>> roland sh-2. First, record in a series of voltages from the sh-2
>> keys, then have the track&hold play them back. With the clock divider
>> triggering it every 4 beats or so, it would act like a recordable one
>> bass note per measure sequencer of sorts.
>>
>> Would that work Or is there a better way to record(track/sample)
>> simple sequences of voltages
> If I understand you correctly: Yes and No.
>
> Basically you are asking some module, which holds certain voltage
> values. Both (S&H and T&H) do this.
> The difference between "Sample and Hold" and "Track and Hold" is, how
> the behave on changes of the ingoing control signal.
>
> S&H:
> After powering the module/system up, a Sample&Hold "listens" to the
> input voltage. The output is 0V. As soon as the control signal changes
> from low(=0V) to high(=5V) the input voltage will be stored in the
> S&H-stage and offered at the output. It does not matter, whether the
> controlsignal is still up or down, and doesn't matter alos whether the
> input signal is changing or not.
>
> T&H:
> After powering the module/system up, also a Track&Hold "listens" to the
> input voltage. The output is 0V. As soon as the control signal changes
> from low(=0V) to high(=5V) the input voltage will fed through to the
> output. The output now will change with the input as long as the control
> signal is high. This is the "Track"-mode: the output tracks the input.
> As soon as the control signal changes back from high to low, the output
> signal (which was changing before) will be freezed at the momentary voltage.
>
> If you compare it to the world of pictures, the S&H is like a photo
> camera, which picks that actual moment. The T&H is similar like a video
> which is sometimes playing sometimes paused.
>
> So: for youre "sequencer" request: yes, multistage S&H and(!) T&H can
> behave like a sequencer, but in recording mode the S&H will behave more
> like expected than the T&H.
>
> Florian
>
>