The Cyber-Spy.Com Usenet Archive Feeds Directly
From The Open And Publicly Available Newsgroup
This Group And Thousands Of Others Are Available
On Most IS NNTP News Servers On Port 119.
Cyber-Spy.Com Is NOT Responsible For Any Topic,
Opinions Or Content Posted To This Or Any Other
Newsgroup. This Web Archive Of The Newsgroup And
Posts Are For Informational Purposes Only.
From: "Bill Sloman"
Subject: Re: Ultrasonics basics
X-Newsreader: Microsoft Outlook Express 6.00.2600.0000
Date: Fri, 22 Nov 2002 00:23:36 GMT
NNTP-Posting-Date: Fri, 22 Nov 2002 11:23:36 EST
Organization: Netlink Customer - reports relating to abuse should be sent to email@example.com
"Dave" wrote in message
> Hello all,
> I want to measure short distances (1 to 2 inches) using reflected
> ultrasonics (i.e. a Tx bouncing back to an Rx). Using 40KHz transducers
> minimum achievable seems to be about 6 inches.
> Looking at existing circuits the transmitter usually sends a burst of 6 to
> 10 pulses? What is the reason for this i.e. why not one pulse? The
> pulse the receiver looks for is surely the reflection of the last pulse
> Is the reason for the 6 inch minimum distance because the transducers
> and so swamp any reflected pulses? If so would a higher frequency be the
> If this is the case are any standard transducers available other than
> So many questions! Does anyone know the answers please?
> Thanks in anticipation, Dave.
IIRR the ultrasonic transducers are fairly hi-Q parts, and driving them with
a shorter pulse still produces the same six to ten cyces of the resonant
frequency; driving them with more cycles gives you a better-shaped pulse in
the air and at the receiver.
Bill Sloman, Nijmegen
Go Back To The Cyber-Spy.Com
Usenet Web Archive Index Of
The sci.electronics.design Newsgroup