VFC32 clarification

Harini Ramanujam

Other Parts Discussed in Thread: VFC32

Hi,

One of our customers is wanting to know if the VFC32 will measure the period of given signal - he will be reading 33Hz and then the plateau changes. Can they measure the period in voltage, or convert the measurement of the period to voltage from the freq? If so, how can they do this?

Thanks,

Harini

over 14 years ago

0 Ron Michallick over 14 years ago

TI__Guru*** 144306 points

Hello Harini Ramanujam,

The VFC32 can convert frequency to voltage.

This will produce the reciprocal of the period.

Can you explain further on the meaning of “plateau changes”?

Regards,
Ron M.

0 Harini Ramanujam over 14 years ago in reply to Ron Michallick

TI__Prodigy 635 points

Hi Ron,

Thanks. Please see below from the customer:

Frequency will not change, 33Hz.The width of the square wave on the o-scope will change form 10% to 90% On.The potential is 24 volts DC.

0 Ron Michallick over 14 years ago in reply to Harini Ramanujam

TI__Guru*** 144306 points

The simplest method is a multi-pole low pass filter. However, the response time will be slow.

Much faster response can be achieved by charging an integrator during the pulse width to get a voltage proportion to pulse width. This voltage must be read before the next pulse or can go to a sample and hold circuit. Then the integrator’s capacitor must be discharged in preparation for the next pulse.

Regards,
Ron M.

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VFC32 clarification