I don't know. Analog signal processing is clearly less memory than a register, no? So a line exists somewhere and I think it's way before no RAM.

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RossBencina a day ago | parent | next [-]

> Analog signal processing is clearly less memory than a register, no?

You are going to have a hard time doing analog signal processing with memoryless elements. In the linear domain all you can do is apply gain and mix signals together. If you work with memoryless nonlinearities you can do waveshaping, which is generally only useful when applied to special signals (e.g. sine waves).

Any time you want to do frequency-dependent behavior (filtering, oscillation) you need energy storing elements, usually capacitors, sometimes inductors. A capacitor is just like a register: it stores charge, similarly, inductors store energy in the magnetic field. Needless to say these devices are not memoryless. In fact, since the quantity that they remember is a continuous variable, they store a lot of information.

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ErroneousBosh 2 days ago | parent | prev [-]

> Analog signal processing is clearly less memory than a register, no?

Bucket-brigade delay lines?

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jayd16 2 days ago | parent [-]

I'm not saying every analog signal processor is surely memory free, simply that you can imagine one that is.

But I'm not really familiar with what that is.

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ErroneousBosh a day ago | parent [-]

They're a kind of analogue dynamic memory. I'd hesitate to call them RAM because the Access is not Random, but they are a kind of shift register and early computers used those for RAM.

Imagine a pair of MOSFETs connected to a pair of capacitors, and a bunch of those joined together in a chain. All the gates of each one of the pair of MOSFETS are connected together, giving you a "left" and "right" clock input.

When you put a signal in if you pulse the "left" and "right" inputs, it'll store the signal voltage in one capacitor, then pass it off to the next capacitor in turn, like old-timey firefighter handing buckets of water down a line of people.

They used to use this for delaying audio signals before digital memory and analogue to digital conversion was cheap enough to use.

	▲	fsckboy a day ago \| parent [-]
		bucket brigades were also used to read large scale sensors like a CCD camera. they are more efficient in their use of die space because you need fewer data paths; they don't need to be digital either, each bucket can be analog for "grey" scale