I need to measure a variable frequency, between 70 and 90 MHz and output a 0-5 VDC voltage level via DAC. I am planning to use an Arduino Due for the project. Can someone guide me to a suitable high-speed (100 MHz?) cascading counter?
Looks like a job for a CPLD, programmed to measure 70-90 MHz in, programmed with parallel or SPI output having 12-bit resolution (0-4095). Then the Due board would write this data to the DAC.
Note that the Due's DAC operates from 1/6 to 5/6 Vcc (0.55 to 2.75V). The hardware SPI on the Due can be configured for 12-bit data with SPI register manipulation. An alternate method for getting an equivalent 0-5V output would be to configure and use a 12-bit PWM output on the Due.
If you're not doing other processing, you could just use a CPLD module connected to an appropriate DAC IC. There is a bit of a learning curve to programming a CPLD, however free software and lots of resources are available ... (just thinking out loud).