- #1
OysteinJ
- 5
- 0
Hi guys & gals.
I work as an electronics engineer in an R&D department, and a discussion with a colleague of mine left me a bit dumbfounded.
Let's say I have a circuit where a high-frequency AC signal is lead to two different paths. In one path the signal remains unaltered, and in the other path the signal is passed through a phase shifter circuit, giving e.g. a phase shift of between -45 and 45 degrees.
Exactly *how* would this phase shifting work? Not the mathematics of it, but if I scope before and after the circuit, how would it look one compared to the other?
180 degrees phase shift is easy enough - it's just the signal "turned upside-down". But I'm struggling with grasping how e.g. a 45 degree phase shift would "look" and what has been done to the signal. Ok, if you talk about 45 degree phase shifting of a 1kHz sinus wave, it'd just be the sinus wave crossing the 0 line 1/8 of 1ms earlier or later. But how about an audio signal from a microphone or a CD?
The circuitry in question is part of a high-frequency radio, where of course horizontal and vertical polarization is possible. So I'm trying to picture that it might be some sort of shifting of the polarization phase. But I can't get that to fit either, given that it's just a voltage in a copper PCB trace.
The other option I'm thinking about is a shift in the phase between voltage and current, which I know some electrical components can introduce (e.g. inductors or capacitors, which introduce a 90 degree phase shift one way or the other between voltage and current).
I know I should *know* this, given that I am an electronics engineer already. But digital electronics were always more my strong suit, to be honest...
Thank you for any and all help on this!
I work as an electronics engineer in an R&D department, and a discussion with a colleague of mine left me a bit dumbfounded.
Let's say I have a circuit where a high-frequency AC signal is lead to two different paths. In one path the signal remains unaltered, and in the other path the signal is passed through a phase shifter circuit, giving e.g. a phase shift of between -45 and 45 degrees.
Exactly *how* would this phase shifting work? Not the mathematics of it, but if I scope before and after the circuit, how would it look one compared to the other?
180 degrees phase shift is easy enough - it's just the signal "turned upside-down". But I'm struggling with grasping how e.g. a 45 degree phase shift would "look" and what has been done to the signal. Ok, if you talk about 45 degree phase shifting of a 1kHz sinus wave, it'd just be the sinus wave crossing the 0 line 1/8 of 1ms earlier or later. But how about an audio signal from a microphone or a CD?
The circuitry in question is part of a high-frequency radio, where of course horizontal and vertical polarization is possible. So I'm trying to picture that it might be some sort of shifting of the polarization phase. But I can't get that to fit either, given that it's just a voltage in a copper PCB trace.
The other option I'm thinking about is a shift in the phase between voltage and current, which I know some electrical components can introduce (e.g. inductors or capacitors, which introduce a 90 degree phase shift one way or the other between voltage and current).
I know I should *know* this, given that I am an electronics engineer already. But digital electronics were always more my strong suit, to be honest...
Thank you for any and all help on this!