65MHz frequency meter based on Microchip's PIC16F648A Frequency reference adopts temperature-compensated voltage-controlled crystal oscillator (±2.5 ppm VC-TCXO) Uses unique gate control method and accurate time algorithm (non-interrupt mode) Frequency measurement accuracy is 10Hz/100Hz (shift one bit to the right) optional Gate (display refresh) time is 0.1 second, real-time display of frequency value Dual intermediate frequency design allows separate preset of intermediate frequency value and plus/minus mode without affecting each other Display driver uses a dedicated chip for LED display; digital tube offers high brightness with minimal external interference Features 6-digit 0.56in digital tube display with automatic blanking of invalid zeros; eight-level brightness is adjustable Simple circuit design with reasonable structure; double button control enables easy operation Various settings can be automatically saved and directly recalled after power-on