high frequency output pulse train by using DAQ 6211

[huangke]

Hi

May i use DAQ USB 6211 to generate a 20 MHz TTL pulse train with amplitude +/-6V? As i know it seems that i cannot use labview and USB 6211 to genertate such function directly. can any body have a strategy to get such pulse train?

Thank you

Best,

[stockson]

Hi huangke,

USB-6211 will not be able to do that. Counter output will have TTL signal levels, and AO is too slow.

Can you tell me why you need to have a +/-6V output?

[huangke]

Hi Stockson,

Thank you for your reply, In fact my goal is to build a driver for a piezo-electric transducer which has a resonat frequency 18 MHz. My idea is to use labview and DAQ USB 6211 to output a TTL pulse train with frequency 18 MHz, I think probably the amplitude should be less than 3 V if i can generate such pulse train with DAQ USB 6211, however, 3 V voltage is not enough for the piezo-electric transducer, so i wonder if i can amplify the pule train.

Thank you

[stockson]

There are multiple voltage level shifters. A lot will depend on number of channels, operating conditions, current requirements etc. Here is an example: http://www.ti.com/lit/ds/symlink/sn74lv1t34.pdf

[Kevin_Price]

In addition to needing an amplifier to get you to the right voltage range and a sufficient current delivery capability:

- does the transducer behave well when driven with a square wave?  In my admittedly limited experience with piezos, we were always careful to generate clean sine waves with very low harmonic content.

- will it behave well when driven at a frequency so far from its resonance?  Your available frequencies with an M-series board and its 80 MHz timebase are either 20 MHz or 16 MHz.  Is this going to be close enough?  With the piezos I dealt with, it wouldn't have been.

-Kevin P

[huangke]

Hi Stockson,

Thank you very much for your information, probably i need to switch to some other methods to build such driver.

[huangke]

Hi Kevin,

Thank you very much for your help. In fact i never worked with piezo before. your experience is valuable to us. It seems that i need to find a special diver for my PZT instead of using labview and the DAQ to drive it.