[email protected] wrote: > Bruce Griffiths wrote: > >> That is a very effective way of elevating the phase noise floor. >> Its usually far better to amplify the input and then split the output >> maintaining a gain to the splitter outputs of at least 0dB. >> >> > As I already explained the last time you mentioned this, > I am well aware of noise floor limitations when operating > an LO or clock at reduced signal levels. > Have you actually estimated the resultant phase noise floor with 0dBm output?? An optimistic estimate can be done using the noise figure at the frequency of interest. > > It is nice to keep the drive levels as high as possible; > however, as long as the overall system noise floor is not > impacted, it really doesn't matter if the reference level > drops somewhere along the way. > When is a noise penalty of around 30dB (for the better sources) not significant?
> > >>> Some data sheets contain this information at spot frequencies; >>> this one does not. >>> >>> >> Very few datasheets from Maxim specify much about the noise >> characteristics of such devices. >> >> > Perhaps we are suffering from a language barrier here. > > When I look at all 21 devices in their "VCOs/VCO Buffers" > parts category, the only ones _without_ noise specs are the > very parts about which I am asking, the MAX274x family. > > Very little useful phase noise data is given (for a distribution amplifier application), particularly for low offset frequencies. For example MAX9989 only gives a spot phase noise at 100MHz output for a 1500MHz input. I was also referring to the lack of low frequency noise data for devices like the MAX477. Maxim aren't alone in this. > Brian > > > Bruce _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
