For an inverting opamp, is inverting the same thing as an 180 degree phase shift?
$begingroup$
Many texts talk about 180 degree phase shift as a function of the inverting opamp.
Is that correct? It seems to me inverting is happening almost immediately but phase is related to time and period and time delay between the input and output.
op-amp
$endgroup$
add a comment |
$begingroup$
Many texts talk about 180 degree phase shift as a function of the inverting opamp.
Is that correct? It seems to me inverting is happening almost immediately but phase is related to time and period and time delay between the input and output.
op-amp
$endgroup$
$begingroup$
Phase is making sense for periodical sinusoidal signals, where phase shift of 180 degrees is equivalent to multiplication by-1
. For other signals it is not the same.
$endgroup$
– Eugene Sh.
6 hours ago
1
$begingroup$
But thats an illusion for the sine case, it just “looks like” phase shifted. Correct?
$endgroup$
– Genzo
6 hours ago
$begingroup$
Yes it is an "illusion" but if it is a pure sinewave, you will be unable to tell the difference so it does not matter, the resulting signal is the same whether you invert of phase-delay.
$endgroup$
– Bimpelrekkie
6 hours ago
add a comment |
$begingroup$
Many texts talk about 180 degree phase shift as a function of the inverting opamp.
Is that correct? It seems to me inverting is happening almost immediately but phase is related to time and period and time delay between the input and output.
op-amp
$endgroup$
Many texts talk about 180 degree phase shift as a function of the inverting opamp.
Is that correct? It seems to me inverting is happening almost immediately but phase is related to time and period and time delay between the input and output.
op-amp
op-amp
edited 35 mins ago
Acccumulation
1133
1133
asked 6 hours ago
GenzoGenzo
366217
366217
$begingroup$
Phase is making sense for periodical sinusoidal signals, where phase shift of 180 degrees is equivalent to multiplication by-1
. For other signals it is not the same.
$endgroup$
– Eugene Sh.
6 hours ago
1
$begingroup$
But thats an illusion for the sine case, it just “looks like” phase shifted. Correct?
$endgroup$
– Genzo
6 hours ago
$begingroup$
Yes it is an "illusion" but if it is a pure sinewave, you will be unable to tell the difference so it does not matter, the resulting signal is the same whether you invert of phase-delay.
$endgroup$
– Bimpelrekkie
6 hours ago
add a comment |
$begingroup$
Phase is making sense for periodical sinusoidal signals, where phase shift of 180 degrees is equivalent to multiplication by-1
. For other signals it is not the same.
$endgroup$
– Eugene Sh.
6 hours ago
1
$begingroup$
But thats an illusion for the sine case, it just “looks like” phase shifted. Correct?
$endgroup$
– Genzo
6 hours ago
$begingroup$
Yes it is an "illusion" but if it is a pure sinewave, you will be unable to tell the difference so it does not matter, the resulting signal is the same whether you invert of phase-delay.
$endgroup$
– Bimpelrekkie
6 hours ago
$begingroup$
Phase is making sense for periodical sinusoidal signals, where phase shift of 180 degrees is equivalent to multiplication by
-1
. For other signals it is not the same.$endgroup$
– Eugene Sh.
6 hours ago
$begingroup$
Phase is making sense for periodical sinusoidal signals, where phase shift of 180 degrees is equivalent to multiplication by
-1
. For other signals it is not the same.$endgroup$
– Eugene Sh.
6 hours ago
1
1
$begingroup$
But thats an illusion for the sine case, it just “looks like” phase shifted. Correct?
$endgroup$
– Genzo
6 hours ago
$begingroup$
But thats an illusion for the sine case, it just “looks like” phase shifted. Correct?
$endgroup$
– Genzo
6 hours ago
$begingroup$
Yes it is an "illusion" but if it is a pure sinewave, you will be unable to tell the difference so it does not matter, the resulting signal is the same whether you invert of phase-delay.
$endgroup$
– Bimpelrekkie
6 hours ago
$begingroup$
Yes it is an "illusion" but if it is a pure sinewave, you will be unable to tell the difference so it does not matter, the resulting signal is the same whether you invert of phase-delay.
$endgroup$
– Bimpelrekkie
6 hours ago
add a comment |
2 Answers
2
active
oldest
votes
$begingroup$
An inverting op-amp inverts the signal; it does not phase change the signal at the output by 180 degrees although, if the input waveform were a sinewave, then it would look like 180 degrees of phase shift.
$endgroup$
$begingroup$
So it “looks like” as if it is phase shifted but actually it is not. There is a nuance here.
$endgroup$
– Genzo
6 hours ago
$begingroup$
@Genzo indeed and a lot of EEs will use the terms interchangeably (including me but I always try and correct these bad habits of mine).
$endgroup$
– Andy aka
6 hours ago
1
$begingroup$
More specifically inverting is equivalent to phase shifting every constituent sine wave in the Fourier representation of the signal by 180 degrees. So in that sense it is equivalent, but potentially miselading in cases where there are other "phases" of interest, such as modulated signals where "invert" is not necessarily the same as phase shifting the modulation by 180 degrees. This is where people get tripped up, phase actually means slightly different things in different contexts.
$endgroup$
– Evan
6 hours ago
$begingroup$
Filters have phase shift and group delay. Inverters have 180 deg inversion
$endgroup$
– Sunnyskyguy EE75
5 hours ago
$begingroup$
Another situation where it matters is if the voltage and current are out of phase.
$endgroup$
– Acccumulation
4 hours ago
add a comment |
$begingroup$
How an opamp behaves depends on how you configure it in a circuit.
But the opamp is actually irrelevant to your actual question.
I think that your actual question is:
Is inverting a signal the same as phase shifting it by 180 degrees
What we mean by inverting a signal is multiplying the signal by -1, so +33mV becomes -33 mV
and -0.5 V becomes +0.5 V.
A 180 degree phase shift is indeed related to time but since phase is also coupled to frequency we only tend to use phase when talking about a single frequency. The only signal that contains a single frequency is a sinewave. Now for a sinewave inverting it (multiply it by -1) or phase shifting it 180 degrees will result in the same signal.
So yes, for sinusoidal signals, inverting and phase shifting with 180 degrees is the same thing.
Also for periodic signals like square waves and sawtooth signals, which consist of a base frequency and harmonics, inverting and phase shifting with 180 degrees is the same thing. Then the phase is only related to the base (lowest) frequency.
For non-periodic signals (these do not have a base-frequency) this isn't the case.
$endgroup$
$begingroup$
"Also for periodic signals like square waves and sawtooth signals, which consist of a base frequency and harmonics, inverting and phase shifting with 180 degrees is the same thing." That makes it sound like it's true of all periodic waves. It's only true of odd waves (i.e. nothing but odd harmonics).
$endgroup$
– Acccumulation
4 hours ago
add a comment |
Your Answer
StackExchange.ifUsing("editor", function () {
return StackExchange.using("mathjaxEditing", function () {
StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix) {
StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["\$", "\$"]]);
});
});
}, "mathjax-editing");
StackExchange.ifUsing("editor", function () {
return StackExchange.using("schematics", function () {
StackExchange.schematics.init();
});
}, "cicuitlab");
StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "135"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);
StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});
function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: false,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: null,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});
}
});
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2felectronics.stackexchange.com%2fquestions%2f418322%2ffor-an-inverting-opamp-is-inverting-the-same-thing-as-an-180-degree-phase-shift%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
An inverting op-amp inverts the signal; it does not phase change the signal at the output by 180 degrees although, if the input waveform were a sinewave, then it would look like 180 degrees of phase shift.
$endgroup$
$begingroup$
So it “looks like” as if it is phase shifted but actually it is not. There is a nuance here.
$endgroup$
– Genzo
6 hours ago
$begingroup$
@Genzo indeed and a lot of EEs will use the terms interchangeably (including me but I always try and correct these bad habits of mine).
$endgroup$
– Andy aka
6 hours ago
1
$begingroup$
More specifically inverting is equivalent to phase shifting every constituent sine wave in the Fourier representation of the signal by 180 degrees. So in that sense it is equivalent, but potentially miselading in cases where there are other "phases" of interest, such as modulated signals where "invert" is not necessarily the same as phase shifting the modulation by 180 degrees. This is where people get tripped up, phase actually means slightly different things in different contexts.
$endgroup$
– Evan
6 hours ago
$begingroup$
Filters have phase shift and group delay. Inverters have 180 deg inversion
$endgroup$
– Sunnyskyguy EE75
5 hours ago
$begingroup$
Another situation where it matters is if the voltage and current are out of phase.
$endgroup$
– Acccumulation
4 hours ago
add a comment |
$begingroup$
An inverting op-amp inverts the signal; it does not phase change the signal at the output by 180 degrees although, if the input waveform were a sinewave, then it would look like 180 degrees of phase shift.
$endgroup$
$begingroup$
So it “looks like” as if it is phase shifted but actually it is not. There is a nuance here.
$endgroup$
– Genzo
6 hours ago
$begingroup$
@Genzo indeed and a lot of EEs will use the terms interchangeably (including me but I always try and correct these bad habits of mine).
$endgroup$
– Andy aka
6 hours ago
1
$begingroup$
More specifically inverting is equivalent to phase shifting every constituent sine wave in the Fourier representation of the signal by 180 degrees. So in that sense it is equivalent, but potentially miselading in cases where there are other "phases" of interest, such as modulated signals where "invert" is not necessarily the same as phase shifting the modulation by 180 degrees. This is where people get tripped up, phase actually means slightly different things in different contexts.
$endgroup$
– Evan
6 hours ago
$begingroup$
Filters have phase shift and group delay. Inverters have 180 deg inversion
$endgroup$
– Sunnyskyguy EE75
5 hours ago
$begingroup$
Another situation where it matters is if the voltage and current are out of phase.
$endgroup$
– Acccumulation
4 hours ago
add a comment |
$begingroup$
An inverting op-amp inverts the signal; it does not phase change the signal at the output by 180 degrees although, if the input waveform were a sinewave, then it would look like 180 degrees of phase shift.
$endgroup$
An inverting op-amp inverts the signal; it does not phase change the signal at the output by 180 degrees although, if the input waveform were a sinewave, then it would look like 180 degrees of phase shift.
answered 6 hours ago
Andy akaAndy aka
240k11178411
240k11178411
$begingroup$
So it “looks like” as if it is phase shifted but actually it is not. There is a nuance here.
$endgroup$
– Genzo
6 hours ago
$begingroup$
@Genzo indeed and a lot of EEs will use the terms interchangeably (including me but I always try and correct these bad habits of mine).
$endgroup$
– Andy aka
6 hours ago
1
$begingroup$
More specifically inverting is equivalent to phase shifting every constituent sine wave in the Fourier representation of the signal by 180 degrees. So in that sense it is equivalent, but potentially miselading in cases where there are other "phases" of interest, such as modulated signals where "invert" is not necessarily the same as phase shifting the modulation by 180 degrees. This is where people get tripped up, phase actually means slightly different things in different contexts.
$endgroup$
– Evan
6 hours ago
$begingroup$
Filters have phase shift and group delay. Inverters have 180 deg inversion
$endgroup$
– Sunnyskyguy EE75
5 hours ago
$begingroup$
Another situation where it matters is if the voltage and current are out of phase.
$endgroup$
– Acccumulation
4 hours ago
add a comment |
$begingroup$
So it “looks like” as if it is phase shifted but actually it is not. There is a nuance here.
$endgroup$
– Genzo
6 hours ago
$begingroup$
@Genzo indeed and a lot of EEs will use the terms interchangeably (including me but I always try and correct these bad habits of mine).
$endgroup$
– Andy aka
6 hours ago
1
$begingroup$
More specifically inverting is equivalent to phase shifting every constituent sine wave in the Fourier representation of the signal by 180 degrees. So in that sense it is equivalent, but potentially miselading in cases where there are other "phases" of interest, such as modulated signals where "invert" is not necessarily the same as phase shifting the modulation by 180 degrees. This is where people get tripped up, phase actually means slightly different things in different contexts.
$endgroup$
– Evan
6 hours ago
$begingroup$
Filters have phase shift and group delay. Inverters have 180 deg inversion
$endgroup$
– Sunnyskyguy EE75
5 hours ago
$begingroup$
Another situation where it matters is if the voltage and current are out of phase.
$endgroup$
– Acccumulation
4 hours ago
$begingroup$
So it “looks like” as if it is phase shifted but actually it is not. There is a nuance here.
$endgroup$
– Genzo
6 hours ago
$begingroup$
So it “looks like” as if it is phase shifted but actually it is not. There is a nuance here.
$endgroup$
– Genzo
6 hours ago
$begingroup$
@Genzo indeed and a lot of EEs will use the terms interchangeably (including me but I always try and correct these bad habits of mine).
$endgroup$
– Andy aka
6 hours ago
$begingroup$
@Genzo indeed and a lot of EEs will use the terms interchangeably (including me but I always try and correct these bad habits of mine).
$endgroup$
– Andy aka
6 hours ago
1
1
$begingroup$
More specifically inverting is equivalent to phase shifting every constituent sine wave in the Fourier representation of the signal by 180 degrees. So in that sense it is equivalent, but potentially miselading in cases where there are other "phases" of interest, such as modulated signals where "invert" is not necessarily the same as phase shifting the modulation by 180 degrees. This is where people get tripped up, phase actually means slightly different things in different contexts.
$endgroup$
– Evan
6 hours ago
$begingroup$
More specifically inverting is equivalent to phase shifting every constituent sine wave in the Fourier representation of the signal by 180 degrees. So in that sense it is equivalent, but potentially miselading in cases where there are other "phases" of interest, such as modulated signals where "invert" is not necessarily the same as phase shifting the modulation by 180 degrees. This is where people get tripped up, phase actually means slightly different things in different contexts.
$endgroup$
– Evan
6 hours ago
$begingroup$
Filters have phase shift and group delay. Inverters have 180 deg inversion
$endgroup$
– Sunnyskyguy EE75
5 hours ago
$begingroup$
Filters have phase shift and group delay. Inverters have 180 deg inversion
$endgroup$
– Sunnyskyguy EE75
5 hours ago
$begingroup$
Another situation where it matters is if the voltage and current are out of phase.
$endgroup$
– Acccumulation
4 hours ago
$begingroup$
Another situation where it matters is if the voltage and current are out of phase.
$endgroup$
– Acccumulation
4 hours ago
add a comment |
$begingroup$
How an opamp behaves depends on how you configure it in a circuit.
But the opamp is actually irrelevant to your actual question.
I think that your actual question is:
Is inverting a signal the same as phase shifting it by 180 degrees
What we mean by inverting a signal is multiplying the signal by -1, so +33mV becomes -33 mV
and -0.5 V becomes +0.5 V.
A 180 degree phase shift is indeed related to time but since phase is also coupled to frequency we only tend to use phase when talking about a single frequency. The only signal that contains a single frequency is a sinewave. Now for a sinewave inverting it (multiply it by -1) or phase shifting it 180 degrees will result in the same signal.
So yes, for sinusoidal signals, inverting and phase shifting with 180 degrees is the same thing.
Also for periodic signals like square waves and sawtooth signals, which consist of a base frequency and harmonics, inverting and phase shifting with 180 degrees is the same thing. Then the phase is only related to the base (lowest) frequency.
For non-periodic signals (these do not have a base-frequency) this isn't the case.
$endgroup$
$begingroup$
"Also for periodic signals like square waves and sawtooth signals, which consist of a base frequency and harmonics, inverting and phase shifting with 180 degrees is the same thing." That makes it sound like it's true of all periodic waves. It's only true of odd waves (i.e. nothing but odd harmonics).
$endgroup$
– Acccumulation
4 hours ago
add a comment |
$begingroup$
How an opamp behaves depends on how you configure it in a circuit.
But the opamp is actually irrelevant to your actual question.
I think that your actual question is:
Is inverting a signal the same as phase shifting it by 180 degrees
What we mean by inverting a signal is multiplying the signal by -1, so +33mV becomes -33 mV
and -0.5 V becomes +0.5 V.
A 180 degree phase shift is indeed related to time but since phase is also coupled to frequency we only tend to use phase when talking about a single frequency. The only signal that contains a single frequency is a sinewave. Now for a sinewave inverting it (multiply it by -1) or phase shifting it 180 degrees will result in the same signal.
So yes, for sinusoidal signals, inverting and phase shifting with 180 degrees is the same thing.
Also for periodic signals like square waves and sawtooth signals, which consist of a base frequency and harmonics, inverting and phase shifting with 180 degrees is the same thing. Then the phase is only related to the base (lowest) frequency.
For non-periodic signals (these do not have a base-frequency) this isn't the case.
$endgroup$
$begingroup$
"Also for periodic signals like square waves and sawtooth signals, which consist of a base frequency and harmonics, inverting and phase shifting with 180 degrees is the same thing." That makes it sound like it's true of all periodic waves. It's only true of odd waves (i.e. nothing but odd harmonics).
$endgroup$
– Acccumulation
4 hours ago
add a comment |
$begingroup$
How an opamp behaves depends on how you configure it in a circuit.
But the opamp is actually irrelevant to your actual question.
I think that your actual question is:
Is inverting a signal the same as phase shifting it by 180 degrees
What we mean by inverting a signal is multiplying the signal by -1, so +33mV becomes -33 mV
and -0.5 V becomes +0.5 V.
A 180 degree phase shift is indeed related to time but since phase is also coupled to frequency we only tend to use phase when talking about a single frequency. The only signal that contains a single frequency is a sinewave. Now for a sinewave inverting it (multiply it by -1) or phase shifting it 180 degrees will result in the same signal.
So yes, for sinusoidal signals, inverting and phase shifting with 180 degrees is the same thing.
Also for periodic signals like square waves and sawtooth signals, which consist of a base frequency and harmonics, inverting and phase shifting with 180 degrees is the same thing. Then the phase is only related to the base (lowest) frequency.
For non-periodic signals (these do not have a base-frequency) this isn't the case.
$endgroup$
How an opamp behaves depends on how you configure it in a circuit.
But the opamp is actually irrelevant to your actual question.
I think that your actual question is:
Is inverting a signal the same as phase shifting it by 180 degrees
What we mean by inverting a signal is multiplying the signal by -1, so +33mV becomes -33 mV
and -0.5 V becomes +0.5 V.
A 180 degree phase shift is indeed related to time but since phase is also coupled to frequency we only tend to use phase when talking about a single frequency. The only signal that contains a single frequency is a sinewave. Now for a sinewave inverting it (multiply it by -1) or phase shifting it 180 degrees will result in the same signal.
So yes, for sinusoidal signals, inverting and phase shifting with 180 degrees is the same thing.
Also for periodic signals like square waves and sawtooth signals, which consist of a base frequency and harmonics, inverting and phase shifting with 180 degrees is the same thing. Then the phase is only related to the base (lowest) frequency.
For non-periodic signals (these do not have a base-frequency) this isn't the case.
edited 6 hours ago
answered 6 hours ago
BimpelrekkieBimpelrekkie
47.9k240105
47.9k240105
$begingroup$
"Also for periodic signals like square waves and sawtooth signals, which consist of a base frequency and harmonics, inverting and phase shifting with 180 degrees is the same thing." That makes it sound like it's true of all periodic waves. It's only true of odd waves (i.e. nothing but odd harmonics).
$endgroup$
– Acccumulation
4 hours ago
add a comment |
$begingroup$
"Also for periodic signals like square waves and sawtooth signals, which consist of a base frequency and harmonics, inverting and phase shifting with 180 degrees is the same thing." That makes it sound like it's true of all periodic waves. It's only true of odd waves (i.e. nothing but odd harmonics).
$endgroup$
– Acccumulation
4 hours ago
$begingroup$
"Also for periodic signals like square waves and sawtooth signals, which consist of a base frequency and harmonics, inverting and phase shifting with 180 degrees is the same thing." That makes it sound like it's true of all periodic waves. It's only true of odd waves (i.e. nothing but odd harmonics).
$endgroup$
– Acccumulation
4 hours ago
$begingroup$
"Also for periodic signals like square waves and sawtooth signals, which consist of a base frequency and harmonics, inverting and phase shifting with 180 degrees is the same thing." That makes it sound like it's true of all periodic waves. It's only true of odd waves (i.e. nothing but odd harmonics).
$endgroup$
– Acccumulation
4 hours ago
add a comment |
Thanks for contributing an answer to Electrical Engineering Stack Exchange!
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
Use MathJax to format equations. MathJax reference.
To learn more, see our tips on writing great answers.
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2felectronics.stackexchange.com%2fquestions%2f418322%2ffor-an-inverting-opamp-is-inverting-the-same-thing-as-an-180-degree-phase-shift%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
$begingroup$
Phase is making sense for periodical sinusoidal signals, where phase shift of 180 degrees is equivalent to multiplication by
-1
. For other signals it is not the same.$endgroup$
– Eugene Sh.
6 hours ago
1
$begingroup$
But thats an illusion for the sine case, it just “looks like” phase shifted. Correct?
$endgroup$
– Genzo
6 hours ago
$begingroup$
Yes it is an "illusion" but if it is a pure sinewave, you will be unable to tell the difference so it does not matter, the resulting signal is the same whether you invert of phase-delay.
$endgroup$
– Bimpelrekkie
6 hours ago