DIY interpolating reciprocal frequency counter FC-510

[Liv]

Interpolating reciprocal frequency counter FC-510

Features:

•   reciprocal counting + interpolation (3-rd generation by Pendulum classification)
•   main input frequency range: 0.1 Hz…100 MHz
•   period range    : 10 ns…10 s
•   measured single pulse duration: 100 ns…10 s
•   measured duty cycle   : 0.0000001…0.9999999
•   measured RPM: 6…999999 rpm.
•   measuring interval: 1 ms…10 s
•   analog interpolator resolution: 1 ns
•   average count: 1…100
•   IF range: ±99.9999 MHz
•   math: Fmin, Fmax, dF
•   hold: yes
•   programmed prescaler ratio: 1…1000
•   prescaler frequency range: up to 2 GHz
•   input impedance: 1 MOhm || 30 pF
•   input coupling: DC+AC, AC
•   input attenuator: 1:1, 1:10
•   sensitivity: 100 mV (up to 50 MHz)
•   max input voltage: ±50 V
•   comparator threshold: –0.5…+0.5 V; –5…+5 V
•   optional LPF: 100 kHz
•   reference: TCXO, ±2.5 ppm (-20…+70°C)

[Liv]

Some photos:

[DmitryL]

+1. I made this frequency meter about a year ago. Works like a charm.
For clocking I used a standard 10Mhz VTCXO with a trimmer resistor for fine freq. adjustment. Calibrated all thing by 1PPS from a GPS receiver.

[Liv]

Firmware version 2.x supports 9-digit frequency display (for 1601 and 1602 LCDs) and level meter in second line (for 1602).

Resolution demonstration (sorry for unintelligible language, I will try to fix):

[DmitryL]

BTW, you forgot to mention that it is a _reciprocal_ counter, not a direct count one.
It makes a huge difference from specs perspective. 

[Liv]

Thank you, I made correction of features list.

[DmitryL]

Don't forget the topic name, it must be eye-catching!

[Liv]

OK, fixed.