<p>The 'DC Component' is a standard term used to describe the mean energy of a signal ( <a href="https://en.wikipedia.org/wiki/DC_bias" rel="nofollow noreferrer">https://en.wikipedia.org/wiki/DC_bias</a> ), which in the frequency domain corresponds to the component of 0 frequency. The DC component does not depend on the time -- while the other frequencies 'wiggle' around it. In seismic signals I think we don't generally have a DC components: the signal moves around a point of 0 pressure/displacement.</p>

<p>The authors then make their statement in a bit of an awkward way in my opinion. What they mean, is that the Hilbert transform applied to any 'DC component' is 0: thrown away!</p>

CC BY-SA 4.0
2018-09-25T20:03:09.160Z
2018-09-25T20:03:09.160Z
Erik
<p>In The Leading Edge tutorial article <em>Phase and the Hilbert transform</em> (Purves 2014), there is the following line:</p>

<blockquote>
  <p>So we apply a Hilbert transform by multiplying all negative frequencies by i and all positive frequencies by -i, leaving any DC component untouched.</p>
</blockquote>

<p>I have two questions following this: </p>

<p><strong>1)</strong> What is the DC component?</p>

<p><strong>2)</strong> What is the significance of not affecting any DC component?</p>

<seismic>
DC component in Hilbert transform concept for seismic data
nate
# DC component in Hilbert transform concept for seismic data

(Asked by: username_0 on 2018-09-23)

In The Leading Edge tutorial article *Phase and the Hilbert transform* (Purves 2014), there is the following line:

> So we apply a Hilbert transform by multiplying all negative frequencies by i and all positive frequencies by -i, leaving any DC component untouched.

I have two questions following this:

**1)** What is the DC component?

**2)** What is the significance of not affecting any DC component?

**Tags:** seismic


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## 1 answers

### Answer by username_1 on 2018-09-25. Score: 1 | Accepted answer

The 'DC Component' is a standard term used to describe the mean energy of a signal ( <https://en.wikipedia.org/wiki/DC_bias> ), which in the frequency domain corresponds to the component of 0 frequency. The DC component does not depend on the time -- while the other frequencies 'wiggle' around it. In seismic signals I think we don't generally have a DC components: the signal moves around a point of 0 pressure/displacement.

The authors then make their statement in a bit of an awkward way in my opinion. What they mean, is that the Hilbert transform applied to any 'DC component' is 0: thrown away!


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