The Adjustable Clock from NetTimeLogic is an adjustable counter clock with nanosecond resolution (second and nanosecond format). It is used by all other cores from NetTimeLogic but can also be used as standalone core. It contains a hardware implemented PI servo loop (which also can be bypassed) for smooth adjustment of drift and offset. Drift and Offset correction are adjusted in parallel and individual. It can take any input frequency, even with non-integer clock periods (e.g. 66MHz) which is handled with fractional subcounters. It has multiple adjustment inputs which are multiplexed to define the source of synchronization.

All calculations and corrections are implemented completely in HW.


Adjustable Clock


  • 32 bit second and 32 bit nanosecond counter clock with fractional extention
  • 1  millisecond pulse generator aligned with the counter clock
  • Allows non-integer clock periods
  • Multiplexing of multiple adjustment inputs
  • AXI4 Light register set or static configuration
  • Evenly spread offset and drift correction (offset might be set hard in case of large offsets)
  • Hard setting of time possible
  • Individual hardware only PI servo loops for offset and drift correction (PI parameters individualy configurable)
  • Offset correction: min 1 ns / s, max 0.5 s/s
  • Drift correction: min 1 ns / s, max 0.05 s/s
  • Conversion of fractional adjustments into even spread clock adjustments
  • Provides time for all other cores

Licensing & Pricing

There are different licensing possabilities. All prices are in US Dollars without VAT, all prices are one-time fees, no royalties apply:

  • Project Source Code:  3600$
  • Site Source Code: 6500$ 

All prices are non-binding estimates – please use the contact form for definitive pricing and lead-time information.


Evaluation binaries available for Digilent's Arty and Terasic's SoCKit develolopment boards or as Modelsim(R) precompiled libraries  => contact us for free access

Clk_Clock_Flyer.pdf Clk_Clock_Flyer.pdf
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Type : pdf
Clk_Clock_ReferenceManual.pdf Clk_Clock_ReferenceManual.pdf
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Type : pdf