Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronic Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

Distance measurements with ultrasonic sensors

Status
Not open for further replies.

gonsays

Newbie level 5
Joined
Mar 25, 2015
Messages
10
Helped
0
Reputation
0
Reaction score
0
Trophy points
1
Activity points
83
Hello guys,

I’m doing a lab regarding Sensors & Actuators, using a ultrasonic 40 kHz piezoelectric emitter-receiver board, in order to do distance measurements, velocity of the sound an thickness measurements.


The modulating signal will be a square-wave with 10 Hz and a duty cycle of 20%.
The carrier will be a 40 kHz sinusoidal signal.

I have some doubts regarding some theoretical questions, if you could help me it would be great:
• Why is it used a 40 kHz signal for the carrier?
• Why is it used a square modulation signal?
• Why is it used a low duty-cycle (20%)?
• Why is it used a DC offset voltage for the modulated signal? [I think it is to prevent overmodulation, right?]
• What is the maximum theoretical distance that can be measured with this signal (carrier 40kHz, modulating signal 10Hz)?

Thank you very much in advance.

Best regards,
G
 

gonsays

Newbie level 5
Joined
Mar 25, 2015
Messages
10
Helped
0
Reputation
0
Reaction score
0
Trophy points
1
Activity points
83
[Moved]Ultrasonic sensor - Theoretical Question

Hello guys,

I would like to ask your help regarding a theorical question regarding an ultrasonic 40 kHz piezoelectric emitter-receiver board, in order to perform distance, velocity of the sound and thickness measurements.

The modulating signal will be a square wave with 10 Hz and a duty cycle of 20%.

The carrier will be a 40 kHz sinusoidal signal.

Having this information, what would be the maximum theoretical distance that can be measured with this signal?

I have found an expression:

va=2.D/ta [velocity of propagation=2*Distance/Time-Of-Flight]

What would be the maximum Distance? Is there any way to relate Time-Of-Flight and the frequency of the carrier/modulating signal?

Any help or tip would be really appreciated.

Thank you in advance :)
 

Status
Not open for further replies.
Toggle Sidebar

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top