I built my homebrew 6-digit frequency counter around two 14553 IC's (similar to the 4553's in the article). It updates each second. Readout 1 to 999,999 Hz. I've had it 30 years.
Timebase is from a 555 IC (10 Hz divided by 10 via 4017 IC). In hindsight I should have made a stable timebase by using a crystal, 32 KHz divided down to 1 Hz via a 4020 counter IC.
You might get away with making updates every 1/10 sec, thus having a range 10 Hz to 10 MHz (by adding a zero to the right of 1-999999).
Or else if the IC's cannot keep pace, then you divide the input by 10 to obtain range 10 Hz to 10 MHz. (So you add a zero to the right of 1-999999.) Updates every sec.
Then dividing by 10 twice is the same as dividing by 100. It gives you 100 Hz to 100 MHz. ( (So you add two zeroes to the right of 1-999999.) Updates every sec.
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I followed schematics in Forrest Mims' Engineer's Notebook. Can be viewed on Google-Books.
https://books.google.com/books?id=a_B4dCFFL2oC&pg=PA32&lpg=PA32