Counte CMOS output pulse

[sugar7]

Hello,

I'd like to know whether there are any couters which can count CMOS output pulse.

The rating of CMOS pulse are:

Output pulse: CMOS 5V

Output pulse width: 10 ns

(It is actually output from Hamamatsu C9744 photon counting unit)

I have some PCI cards (6014 and 6110), but their counter logic is TTL, not CMOS.

When the CMOS output is connected to a counter of these cards, the counter number

increased, but this may not be a correct counting.

If you have a good idea to count with NI products, please let me know.

Thank you for your time and kind help.

Hiro

[JL@NI]

Hello Hiro,

I was able to locate, in the Timing I/O section, some specifications in the manuals of the NI PCI-6014 and NI PCI-6110. Based on these specifications, both of your cards are TTL/CMOS compatible and can handle a minimum pulse width of 10ns. Links to these manuals are as follows:

NI PCI 6013/6014

NI PCI-6110/6111

My only concern is that the maximum external source frequency must be below 20 MHz. If the frequency of your signal is above this, your counter will be missing pulses. If your signal frequency is above 20 MHz, please feel free to let me know and we can help you find something better suited for your application.

Thanks,

Jeff L.

[sugar7]

Hello Jeff,

Thank you for your information.

The max frequency of 20 MHz is enough for our application.

However, your answer made me confused a little bit.

Do you mean that the counter can count CMOS pulse?

According to the specifications of, for example, PCI-6110 (https://www.ni.com/en-us/support/model.pci-6110.html)

The logic level of the counter is TTL.

I guess my measurement is correct only when the input CMOS has a well controlled low level signal less than the TTL threshold.

All of your products have counters only for TTL, is it right?

best regards,

Hiro

[JL@NI · Accepted solution]

Hey Hiro,

The bottom line is that a TTL counter will be able to read from CMOS input, but not the other way around. Therefore, you are OK. 

An explanation of the voltage thresholds associated with each standard can be found in the graph in this link:http://www.interfacebus.com/voltage_threshold.html

The counters on your devices fall under TTL/CMOS standards, which can count a CMOS pulse input.

Regards,

Jeff L.