UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post

RobinBirch · 20th Dec 2007, 3:23 pm

Hi,
I am toying with the idea of building a frequency standard tied to the Radio 4 droitwich signal.

As I understand it, most of these devices consist of a 198 kHz receiver and then a set of phase locked loops using the receiver as the base clock. Each of the loops gives out the reference frequency you want, say 1 MHz, 10 MHz and so on.

I am assuming that the divide or multiply circuits that are used in the PLLs should be whole numbers so that you are matching the base frequency as closely as possible. Given that 198 kHz is a mathematically inconvenient number what is a reaonable set of multipliers?

Also, has anyone got a circuit for such a thing that I could have a look at?

Cheers

Robin

20th Dec 2007, 3:23 pm	#1
RobinBirch Hexode Join Date: Apr 2003 Location: Cotswolds, UK. Posts: 465	Frequency Standards Hi, I am toying with the idea of building a frequency standard tied to the Radio 4 droitwich signal. As I understand it, most of these devices consist of a 198 kHz receiver and then a set of phase locked loops using the receiver as the base clock. Each of the loops gives out the reference frequency you want, say 1 MHz, 10 MHz and so on. I am assuming that the divide or multiply circuits that are used in the PLLs should be whole numbers so that you are matching the base frequency as closely as possible. Given that 198 kHz is a mathematically inconvenient number what is a reaonable set of multipliers? Also, has anyone got a circuit for such a thing that I could have a look at? Cheers Robin