DIY interpolating reciprocal frequency counter FC-510

• DIY interpolating reciprocal frequency counter FC-510
  Posted by Liv on 05 Mar, 2015 13:27
• 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)
  

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  FC-510_sch_v2.pdf

  fp-510_pcb_v2.pdf

  FC-510_labels.pdf

  FC-510_firmware_source_v20.zip

  

  

  

  
• #1 Reply
  Posted by Liv on 05 Mar, 2015 13:29
• Some photos:
  

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• #2 Reply
  Posted by DmitryL on 05 Mar, 2015 13:45
• +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.
• #3 Reply
  Posted by Liv on 05 Mar, 2015 16:03
• 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):
  
  
  
  
• #4 Reply
  Posted by DmitryL on 05 Mar, 2015 16:42
• BTW, you forgot to mention that it is a _reciprocal_ counter, not a direct count one.
  It makes a huge difference from specs perspective. 
• #5 Reply
  Posted by Liv on 05 Mar, 2015 17:02
• Thank you, I made correction of features list.
  
• #6 Reply
  Posted by DmitryL on 05 Mar, 2015 17:06
• Don't forget the topic name, it must be eye-catching!
• #7 Reply
  Posted by Liv on 05 Mar, 2015 17:13
• OK, fixed.