Cecile at 14:28, 10 March 2010

2010-03-10T14:28:25Z

Cecile: New page: The selection of the frequency bands to be processed is driven by parameter inputs inside the ''Processing'' tab of the FK and MSPAC toolboxes. In the ''Frequency sampling'' layout group y...

2010-03-10T13:35:32Z

New page: The selection of the frequency bands to be processed is driven by parameter inputs inside the ''Processing'' tab of the FK and MSPAC toolboxes. In the ''Frequency sampling'' layout group y...

New page

The selection of the frequency bands to be processed is driven by parameter inputs inside the ''Processing'' tab of the FK and MSPAC toolboxes.
In the ''Frequency sampling'' layout group you can specify the minimum and the maximum (central) frequencies for processing.
Between these two limits, the frequency axis will then be sampled according to the settings in the next line [[Image:FKFreqSampling.png|250px]].

There are two options to be specified, namely ''Step'' and ''Number of Samples''. For the ''Step'' parameter, there are two options to be selected from a drop box: ''Log'' or ''Linear''. You might have guessed the meaning right away. When choosing ''Linear'' then the frequency axis is sampled linearly between the given limits and exactly ''Number of Samples'' will be distributed along the axis. Choosing ''Log'' accordingly samples the frequency axis logarithmically, i.e. frequency bands are ''close'' spaced at lower frequencies.

Note: the sampled frequencies are taken as '''center frequencies''' in the processing scheme. Therefore, it is necessary to specify additionally a bandwidth so that the processing can be performed in a finite but narrow frequency band.
* For FK and HRFK processing, the bandwidth parameter is chosen by the user and chosen as relative half-bandwidth in the ''FK-gridding'' layout group in the ''processing tab'' [[Image:FKGridding.png|250px]].
* For MSPAC, the bandwith is set 0.1 by default

The frequency limits for each frequency band are computed as
<math>
[(1-bw)\cdot f_c,(1+bw)\cdot f_c]
</math>
where <math>f_c</math> is the central frequency and <math>bw</math> is the bandwidth parameter.

Example: a setting of 0.10 for the bandwidth, a ''Linear'' spacing of 10 samples along the frequency axis from 1 Hz to 10 Hz will create the following frequency bands:
{| border="1" cellpadding="2" cellspacing="0"
|+ align="bottom" style="color:#e76700;" |Frequency band creation using ''Step'': Linear, ''Bandwidth'': 0.10, ''From'': 1 Hz, ''to'': 10 Hz
! Freq. band index
! Lower frequency limit
! Center frequency
! Upper frequency limit
|-
| 1
| 0.9 Hz
| 1.0 Hz
| 1.1 Hz
|-
| 2
| 1.8 Hz
| 2.0 Hz
| 2.2 Hz
|-
| 3
| 2.7 Hz
| 3.0 Hz
| 3.3 Hz
|-
| 4
| 3.6 Hz
| 4.0 Hz
| 4.4 Hz
|-
| 5
| 4.5 Hz
| 5.0 Hz
| 5.5 Hz
|-
| 6
| 5.4 Hz
| 6.0 Hz
| 6.6 Hz
|-
| 7
| 6.3 Hz
| 7.0 Hz
| 7.7 Hz
|-
| 8
| 7.2 Hz
| 8.0 Hz
| 8.8 Hz
|-
| 9
| 8.1 Hz
| 9.0 Hz
| 9.9 Hz
|-
| 10
| 9.0 Hz
| 10.0 Hz
| 11.0 Hz
|}

@@ Line 7: / Line 7: @@
 Note: the sampled frequencies are taken as '''center frequencies''' in the processing scheme. Therefore, it is necessary to specify additionally a bandwidth so that the processing can be performed in a finite but narrow frequency band.
 * For FK and HRFK processing, the bandwidth parameter is chosen by the user and chosen as relative half-bandwidth in the ''FK-gridding'' layout group in the ''processing tab'' [[Image:FKGridding.png|250px]].
-* For MSPAC, the bandwith is set 0.1 by default
+* For MSPAC, the bandwith is set to 0.1 by default and can not be modified.
 The frequency limits for each frequency band are computed as

Geopsy: Sampling Frequency - Revision history

Cecile at 14:28, 10 March 2010

Cecile: New page: The selection of the frequency bands to be processed is driven by parameter inputs inside the ''Processing'' tab of the FK and MSPAC toolboxes. In the ''Frequency sampling'' layout group y...