How does Decawave DW1000 sample UWB signals?


This is more like a concept question. I am wondering how DW1000 can sample GHz UWB signals while just using a 38 MHz oscillator. I would appreciate any help.


In exactly the same way as your PC processor run at 2 GHz when the clock input to it is also around 30 MHz.
Inside the chip is a PLL (Phase locked loop which multiplies the input clock up to the required speed.

It is very rare for an IC to have an input clock over around 50 MHz, most aim for somewhere between 10 and 40 MHz. This is for a number of reasons: The clock is normally generated by a piece of quartz crystal that is physically vibrating at the required speed, since it’s tied to a physical movement there are limits on what can easily be made reliably. When designing a PCB the higher the speed a signal changes the more careful you have to be about how you connect it. It takes a lot more power to a voltage than the maintain it, the higher the clock speed the more power required to drive the clock input.

PLLs are cheap and fairly standard bits of circuit these day so it’s a lot easier to input a low speed clock that multiplies up to the final frequency and then use a PLL.