Supercon 2024: Using An Oscilloscope To Peek Below The Noise Floor

When you’re hunting for a signal with your oscilloscope, the stronger it is, the better. If it’s weak, you might struggle to tease it out from other interference, or even from the noise floor itself. You might wish that you were looking for something more obvious rather than the electromagnetic equivalent of a needle in a haystack.

Finding hidden signals below the noise floor may be a challenge, but it needn’t be an insurmountable one. James Rowley and Mark Omo came to the 2024 Hackaday Superconference to tell us how to achieve this with the magic of lock-in amplifiers.

Continue reading “Supercon 2024: Using An Oscilloscope To Peek Below The Noise Floor”

Lock In Amplifiers

If you have about an hour to kill, you might want to check out [Shahriar’s] video about the Stanford Research SR530 lock in amplifier (see below). If you know what a lock in amplifier is, it is still a pretty interesting video and if you don’t know, then it really is a must see.

Most of the time, you think of an amplifier as just a circuit that makes a small signal bigger in some way — that is, increase the voltage or increase the current. But there are whole classes of amplifiers designed to reject noise and the lock in amplifier is one of them. [Shahriar’s] video discusses the math theory behind the amplifier, shows the guts, and demonstrates a few experiments (including measuring the speed of sound), as well.

Continue reading “Lock In Amplifiers”