2.6 Basic Processing

df

shows FID

ft

Fourier transform

wft

Fourier transform weighted by the appodization function

ds

Show spectrum

full

Makes the spectrum fit the window

dscale

Show scale

axis='h'

Changes scale to hertz

axis='p'

Changes scale to ppm

lb=n

Linne broadening (n is a number). You multiply a the FID by a function like . Others apodization functions are gf (gaussian), gfs (shifted gausian), sb (sinbell) and ssb (shifted sinbell).

fn=n

Number of points in the Fourier Transformation (n is a number). If your FID has 20000 points and fn=32K (must be a multiple of 2), the diference is added as zero in the end of the FID.

vsadj

Vertically adjust the spectrum to the screen

vs=n

A variable for the peaks height in the screen. n is a number, constantly shown on the DPS panel (2) when showing a spectrum.

wti

Graphical control over lb.

dc

Correct line base by making the end points of the spectrum in the same level.

dpf

shows frequecies of lines above threshold. First set the threshold level by typing ds, clicking , and then clicking on the DPS panel (2) on the level you want to set the threshold line.

dssh

Display arrayed spectra. To display each second spetrum from the increment 3 to the increment 9 type dssh(3,9,2).

dssl

Display arrayed spectra labels

vp=n

Sets the height of the spectrum (base line) on the screen. n is a number, constantly shown on the DPS panel (2) when showing a spectrum.

Expanding a Region in The Spectrum (For Vnmr)

1. Click - - - -.
2. Use right-left click to define the region
3. Click or a zoom picture button in VnmrJ
4. Type f to see whole spectrum
5. Comandos s1, s2, ... salve expansions 1, 2, ... and comands r1, r2, ... show them in the screen

Phase correction

1. Try aph, aph0 or aphx for automatic phasing or
2. Click and right-click in one side the spectrum and sweep vertically while pressing (left click is fine control).
3. Do the same in the other side of the spectrum

Base Line Correction

If the line base is like a wave you can try linear prediction. If it is irregular you can try bc. First integrate the peaks of your interest. For that click (ds can make it appear), and use the mouse to set the integral limits. Then type bc and everything out of the integrals will be zero (peaks can make litle distortion).

Calibrating/Listing Lines

1. Place cursor in the reference line and type nl to find the nearest line
2. rl(7.27p) sets the peak frequency to 7.27ppm
3. dscale shows scale
4. For listing the peaks, type ds, click , and adjust the height. For printing them use the option ppf or ppp. Example: pl ppf page.
5. dll lists peaks (above the treshold) chemical shifts in the spectrum window
6. fp saves the list from the command dll for processing (like T1 calculation).
7. dpf and dpfhz list peaks/values in the text window

Integrating

1. (or - - to see it)
2. cz to clean previous processing
3. Adjust integral intensity with midle-click
4. Buttons and adjust integral lines with mouse
5. and left click set left limits for integrals
6. Place cursor inside a integral region and press to set value of this integral.

Signal to Noise Ratio

1. Select with that cursors a region with only noise in the spectrum
2. Type dsnmax

Other Important Commands

lsfid=n:

makes left-shift of the FID, ie cuts the n first points of it (see also lsfid1, lsfid2)

rp/lp=n:

zero and first order phase correction. If you got lost in phasing, set them to zero and start again.

fiddle:

sets best parameters values in order to resolve one signal.