Reply-To: "Kevin Aylward"
From: "Kevin Aylward"
Subject: Re: Detecting original ultrasonic signal vs. reflected?
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Date: Wed, 25 Sep 2002 10:39:00 +0100
NNTP-Posting-Date: Wed, 25 Sep 2002 10:39:08 BST
"John Rahn" wrote in message
> Hi all.
> Is it at all possible, to tell the difference, of a reflected
> ultrasonic signal to an original signal.
> I am starting a project that sends a signal from a transmitter to
> separate receivers and want to try to figure out how to detect/filter
> out reflected signals, because I will be timing the received signals,
> and a reflected signal would cause an inaccurate reading.
> Also, is it possible to use a carrier to send separate, distinct (yet
> simple) signals, like an RF signal?
> Uhhhh ... just wondering.
> Jeez ... I should have studied more in school.
> Thanks in advance.
For a simple ultrasound system, in pulsed mode, you send a couple of
pulses at most, and blank the receiver during that time. Tx and Rx are
separated in time!
For continuous mode, e.g. Doppler velocity determination, the received
signal is at a shifted frequency.
SuperSpice, a very affordable Mixed-Mode
Windows Simulator with Schematic Capture,
Waveform Display, FFT's and Filter Design.