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Azur Electronics

The HP 5316A Universal Counter measures frequencies in the range of DC up to 100MHz. It cost $1,900 in 1987. A Manual was available for download, plus HP Application Note AN200 Fundamentals of Electronic Counters.

Front view with A & B Channel inputs
The 5316A can also measure period, time interval average, time interval (holdoff) delay, and ratio. A totalise function with manual or external gating is also provided. All measurements, except totalise, are displayed in engineering notation (ie 75.000000 E6 Hz instead of 75MHz) with up to 8 digits of resolution on a red led display. This makes it a useful Counter for less common frequency and time measurements. 

Rear view with HP-IB and REF I/O connections

Input A and B
Frequency Range: DC coupled 0 to 100MHz; AC coupled 30Hz to 100MHz
Sensitivity: 10mV rms to 10MHz; 25mV rms to 100MHz, 75mVpp pulse with minimum pulse width of 5ns
Impedance: 1MΩ
Timebase Output: 10MHz 50mVpp into 50Ω


Front Panel
Input A BNC Female
Input B BNC Female

Rear Panel

Reference Input/Output BNC Female. Depending on Reference switch position Int / Ext, this is either timebase output or frequency reference input. The 5316A does not actually use the external input signal for a timebase but locks-on with an injection-lock multiplier. The external signal must be 1, 5 or 10MHz at 500mV rms across 500Ω. HP-IB.

November 2007

Cleaned up and all in good condition, apart from a small crack in the front panel perspex cover. Performance tests carried out.

June 2009

The 5316A is generally used with an external 10MHz oven-controlled oscillator from the HP 5342A Microwave Frequency Counter via the Azur SDU106 Signal Distribution Unit. This "locks" all the counters together to provide more accurate measurements.

December 2016

The 5316A is not displaying the frequency from Channel A.  Power-up self-check gives E3 error code and HP-IB LEDs flashing out of phase.  Troubleshooting from the Manual identified no Reference Oscillator output. This was due to bad contacts on the rear panel INT/EXT switch. Removing the HP-IB PCB provides access to the switch for contact cleaner. Now all working again.

Interestingly, the maximum frequency is 99.999999 E6 Hz as 100MHz indicates over-range.