High Sensitivity 1Hz-50MHz Frequency Meter

Features:
Frequency range: 1Hz-50MHz(in fact, it can work up to 78MHz).
Four or five digits resolution(display for example, x.xxx KHz, x.xxx MHz, or xx.xx MHz).
Automatic range switching with different gate times.
Programmable addition or subtraction of the frequency offset.
Input impedance: 1.1M, in parallel with about 10pF.
Input sensitivity: tipcally less than 20mV RMS from 1Hz-100KHz, rising to 35mV at 20MHz and 75mV at 50MHz(150mV at 78MHz).
Current consumption: 50mA with 7 to 9V input.
Optional(configurable) power-saving mode which automatically turns the display off if the frequency didn't change significantly within 15s.