ERROR-Doppler Additional Topics part 1 at 17:02 Option A is rightfully incorrect also, as the HIGH PASS wall filter eliminates low velocity signals which are due to tissue motion. Tissue motion has low velocity high amplitude signals so in that sense the HIGH PASS wall filter does eliminate high amplitude signals due to tissue motion. High pass wall filters eliminated low frequency and high amplitude signals Low pass wall filters eliminated high frequency and low amplitude signals There is also confusion regarding the “REJECT” function of the ultrasound receiver, as some systems use the terms wall filter and reject interchangeably, YIKES. Sorry for the confusion. Special thanks to Tariq Naseem and Antonio Hernandez and others who alerted us to the error. We will re-record the lecture and remove the error when time permits. Sorry for the mistake.