2Mhz Frequency Counter Circuit
This is a schematic and block diagram of a 2-MHz frequency counter. It uses and LSI counter/display driver, LCD readout, and a few logic chips for timebase and timing pulse circuitry. Q2 and Q3 form a signal (input) amplifier. The circuit contains a crystal oscillator built around U3- c and XTAL1, which provides the primary timing-reference signal. That signal is then divided twice to provide two additional timing references, giving the circuitry three selectable timing references.
The ICM7224IPL is an integrated circuit that consists of the counter and display driver to drive the LCD-004 display.