RIGOL 
3-4                                                   © 2008 RIGOL Technologies, Inc. 
  User’s Guide for DS1000B Series 
Example 4: To Reduce the Random Noise on a Signal 
If the signal is noisy (Figure 3-2), set up the oscilloscope to reduce the noise on the 
waveform and avoid its interference to the signal. 
 
Figure 3-2 
Waveform display 
 
1.    Set the probe and the channel attenuations to 10X. 
2.    Connect a signal to the oscilloscope and obtain a stable display. 
3.    Improve the trigger by setting the Coupling 
1)  Press the MENU in the Trigger control area. 
2)  Press Set UpėCouplingėLF Reject or Press Set UpėHF RejectėON. 
HF Reject (High frequency rejects) adds a low pass filter with the -3 dB cut-off 
point at 150 kHz. Use HF rejects to remove high frequency noise such as AM or 
FM broadcast stations from the trigger path. 
LF Reject (Low frequency rejects) adds a high pass filter with the -3 dB cut-off 
point at 8 kHz. Use LF Reject to remove low frequency signals such as power 
line noise from the trigger path. 
4.  To reduce the noise by setting the acquisition type and adjust the waveform 
intensity