YOKOGAWA DL750 User Manual

15-8
IM 701210-06E
15.3 Using Filters (DSP Channels)
Explanation
A digital filter is used to perform the computation.
Computed Channels
CH1 to CH16 and DSP1 to DSP6 (optional)
The computed result of a DSP channel can be specified as a computation source of
another DSP channel, but only DSP channels with a channel number smaller than itself
can be specified.
Setting the Digital Filter
The following four types of filters are available. For details, see Appendix 6.
Sharp, Gauss, Mean (moving average), and IIR (Butterworth)
Filter Format Characteristics Filter Computation
Type Type
Sharp Steep attenuation slope (–40 dB per octave) LPF
1
FIR
Linear phase and constant group delay HPF
1
Ripple exists in the passband BPF
1
Stop band is comb-shaped
Gauss Gentle attenuation slope LPF FIR
Linear phase and constant group delay
No ripple in the passband
There is no overshoot in the step response.
Low order and small delay
MEAN Comb-shaped characteristics LPF FIR
(Moving Average) There is no overshoot in the step response.
Linear phase and constant group delay
IIR Attenuation slope is between SHARP and GAUSS LPF IIR
(Butterworth) Not linear phase and group delay not constant HPF
No ripple in either passband or stopband BPF
Close to the characteristics of an analog filter
Cutoff frequency can be set lower than SHARP/GAUSS
1. LPF, HPF, and BPF denote low-pass filter, high-pass filter, and bandpass filter, respectively.
The cutoff frequency, center frequency, and pass band can be specified in terms of
percentages of fs (sampling frequency).
Type Filter Band
1
Cutoff Frequency
2
Center Frequency
3
Pass Band
4
Sharp LPF 2.0% to 30.0% - -
HPF 2.0% to 30.0% - -
BPF - 3.0% to 30.0% 2% of fs
- 4.6% to 30.0% 5% of fs
- 7.0% to 30.0% 10% of fs
- 9.6% to 30.0% 15% of fs
- 12.0% to 30.0% 20% of fs
Gauss LPF 2.0% to 30.0% - -
IIR LPF 0.2% to 30.0% - -
HPF 0.2% to 30.0% - -
BPF - 0.6% to 30.0% 1% of fs
- 1.2% to 30.0% 2% of fs
- 2.6% to 30.0% 5% of fs
- 5.2% to 30.0% 10% of fs
- 7.6% to 30.0% 15% of fs
- 10.2% to 30.0% 20% of fs
1. LPF, HPF, and BPF denote low-pass filter, high-pass filter, and bandpass filter,
respectively.
2. The cutoff frequency (CutOff) can be specified only when LPF or HPF is selected.
The resolution is 0.2%.
3. The center frequency can be specified only when BPF is selected.
The resolution is 0.2%.
4. The pass band can be specified only when BPF is selected.
You can select the pass band from 1%, 2%, 5%, 10%, 15%, and 20%.

YOKOGAWA DL750 Specifications

General

Brand	YOKOGAWA
Model	DL750
Category	Measuring Instruments
Language	English