audiodelayoperational-amplifier
I would like to make a circuit that causes an audio delay using discrete components.
I know I can do small phase shifts using an opamp, but I am looking for something in the millisecond or second range.
Is there any way, at least easily, to do this with discrete components?
EDIT: I would like to know this for both the purposes of synchronization as well as reverb and such. This may take two completely different paths, but both paths are applicable to work I will be doing.
If you want something simple to get started you could build this class A amplifier:
(from this excellent site).
\$R_E\$ stabilizes the DC setting, the bypass capacitor \$C_E\$ is needed to allow an AC signal to change the output, otherwise \$R_E\$ would try to keep the output constant.
A class A amplifier is not very efficient. There will always flow a current through it to keep the output at Vcc/2.
First of all, I am wondering if this is how it's actually done: i.e. when Intel makes a CPU, do they build all the registers, etc. using
NAND/NORgates, or do they have some other fancier way of doing things?
Registers aren't made out of gates, most often they are dedicated circuits. They can be seen as made with inverters (NOT), but only to a certain extent.
In CMOS technology, everlogic circuit is based on the inverter: NOR and NAND gates are just inverters with multiple inputs arranged in a clever way, basically. So the inverting gates are faster than non inverting ones, which are just inverting gates with a NOT at the output.
Also in dynamic logic, it's simpler to cascade two inverting blocks than putting NOT gates everywhere.
Consider that in some cases a circuit may be made out of separated blocks, so there may be a case in which the output is interfaced through one or more inverters for buffering.
And there is another advantage in that: integration. Having a small number of different gates helps in laying out the circuit, and uniforming the performance. Often libraries include logic blocks at different levels of complexity: transistor, gate, operator, or higher.
So, briefly, yes, fast processors are mostly using inverting gates.
Best Answer
One common method is to use a circuit know as a bucket brigade.
These circuits consist of a chain of capacitors. Connecting the capacitors are switches. By driving the control signal for the switches the signal is transferred from one capacitor to the next each time the control (or clock) signal transitions. The time delay you can achieve is limited by the number of stages you have and the slowest sampling rate you can tolerate.
Because you need many stages to create a longer delay it is not really practical to implement this with discrete components. There are a few ICs that implement the function varying from 512 to 4096 stages. With 4096 stages a 20kHz sampling rate will give you 100 ms of delay. You could cascade a number of delay lines together, but you will be losing signal quality with each section.
If signal quality and the length of the delay is important, then digital sampling techniques will be very hard to pass up.