HEIDENHAIN PWM 20 - Manual (Page 210)

November 2014 Interface description 211
Recommended input circuit of the subsequent electronics 11 µApp
Dimensioning Operational amplifier e.g. RC 4157
R = 100 k
  2 %
C = 27 pF
U
B
=
 15 V
U
1
= typ. 2.5 V
3 dB cutoff frequency of the circuit
Approx. 60 kHz
Circuit output signals
= x 2R
U
a
= typ. 2.2 Vpp
Signal monitoring
A threshold of 2.5 µApp is to be provided for the monitoring of the output signals.
Cut-off frequency The cutoff frequency indicates the scanning frequency at which a certain fraction of the original
signal amplitude is maintained.
 3 dB cutoff frequency: 70 % of the signal amplitude
 6 dB cutoff frequency: 50 % of the signal amplitude
U
a
I
pp