Digital filter problem on 400WB(Date
posted:
The problem: spikes during signal acquisition - detected when working on the 400WB through xwinnmr.
Work-around: The problem was found to occur only when working with a digital filter of type medium (the parameter is 'DSPFIRM'). Therefore change this parameter to 'sharp (standard)'
eda --> DSPFIRM --> sharp (standard)
'Wiggly' baseline on 400WB(Date
posted:
The problem: Detected when working on the 400WB with Xwinnmr. After 'FT', the spectrum has a strong 'sine' modulation of the base-line.
Workaround: The problem was shown to be caused by a strong 'spike' at the end of the FID. It was detected only when working with digital filter, and it is very likely that it happens only with 'DSPFIRM = medium' (see entry no. 1). It can be solved retrospectively (i.e., even after acquisition) by changing the parameter tdeff. This parameter should be set to 'td-2'. For example: if td = 4k, set tdeff = 4094.