Multipliers

Hi Reza ,

I looked into the compare tab on the same product page of SN74284 for all the multipliers and timers portfolio we offer and I have it here .CD4521 is a an option you can consider . SN74LS292 /294 can also be looked into .

Reza,

I'm not sure I understand your request.

I think you said the you have a 100ms clock (10Hz) and you want to divide the clock by 600 to get a 60s clock (one cycle per minute 30 seconds high, 30 seconds low).

Ron Michallick said:

Reza,

I'm not sure I understand your request.

I think you said the you have a 100ms clock (10Hz) and you want to divide the clock by 600 to get a 60s clock (one cycle per minute 30 seconds high, 30 seconds low).

Hi Ron

Thanks for the response. The pulse train is around 4KHz max. I sample this at a rate of 100ms and then I count the number of count in 100ms then I want to convert this count back to minute, which is first 100ms multiply by 10 to get to second and then multiply by 60 to get to minute. so in total I want to multiply the count by 600.

I hope I explained myself .

Regards

Reza

Hi Sheryas

thanks for the response. I am not sure how I can achieve a multiplication by frequency divider i.e 5421. Let me explain what I am doing. I have a Turbine engine that it revs up to 250,000 RPM. I want to build a 6 digits tachometer for the test rig to display the RPM on 6 digit 7 segment display. I know I can do this with Arduino but I just set a target for myself to do it with logic circuit as I think it will be more fun to do it. so I count the pulses for 100ms (my sample rate) convert it to binary then multiply it by 600 to get it to Rev per minute and then display it. you see I already have made a test circuit with 74284 and 74285 and it multiplies 4 bit by 4 bit but I can not find any more of these ICs in Canada and plus it is obsolete so I can not reproduce the test rig. hence I want to see if there are any equivalent Ics available. I can see Rate multipliers but I dont think I can achieve what I did with 284 and 285. I hope it is now more clear for you.

thanks for your help.

Regards

Reza

Reza,

I expect the final result will be BCD. (decimal)
So multiplying by 600 will result in the units and tens digit to be always "0"

Therefore I suggest us counting with BCD counters over a 600mS time period.
This will give 100RPM resolution.

If that refreshes to slowly then try 60mS for a 1000 RPM resolution.

You still get the fun of latching and clearing the counter. Not to mention the BCD to 7 segment decoders.
Get Nixie tubes if you can

Reza, one last piece of advice.

X10 is add a zero digit, do that twice.
6*n is 4n + 2n
That simplifies to n shift left 2 bits added with n shift left 1 bit (you get a free static 0 bit, to go with your two 0 digits)
Now you only need full adders.

Good luck.