That is almost true, depending on the PhFreq. discriminator In a message dated 12/12/2018 3:56:49 PM Eastern Standard Time, [email protected] writes:
The TI/NationalSemiconductor LMX2594 and LMX2595 have the best phase noise floor FOM at -236. The AnalogDevices/LinearTechnology LTC6952 has the best flicker at -281. It requires an external VCO. The LTC6951 with an on board VCO is almost as good. Although these are state of the air for a synthesizer-on-a-chip, it is easy to beat them if you roll your own with a mixer as a phase detector. Rick N6RK On 12/12/2018 12:44 PM, Ulrich Rohde wrote: > Who makes it ? > > In a message dated 12/12/2018 3:43:23 PM Eastern Standard Time, > [email protected] writes: > > FWIW, the HMC832 has FOM of -226. The best synth on a chip > now available AFAIK has FOM of -236. That's 10 dB better. > > Rick N6RK > > On 12/12/2018 10:46 AM, Dr. Ulrich L. Rohde via time-nuts wrote: > > I did some phase noise measurement and the 8751 is much better then the > > rest on the market > > > > Sent from my iPhone > > > >> On Dec 12, 2018, at 1:20 PM, Bob kb8tq <[email protected] > >> <mailto:[email protected]>> wrote: > >> > >> Hi > >> > >> Just to save others the time digging, the 7851 uses a HMC832 VCO + > >> fractional N PLL on a chip as > >> the heart of its synthesizer. Yet another “way to go” if building a quick > >> and simple signal source. > >> > >> === > >> > >> No argument at all about other parts of the radio having their limits. PA > >> performance certainly is one > >> of those areas. > >> > >> Bob > >> > >>> On Dec 12, 2018, at 12:42 PM, Dr. Ulrich L. Rohde via time-nuts > >>> <[email protected] <mailto:[email protected]>> wrote: > >>> > >>> My feeling is > >>> A Because of the low sunspot cycle the large signal performance of the RX > >>> is less a topic, the ICOM 7851 dynamic range, synthesizer and frequency > >>> concept is winning but expensive > >>> B The power amplifier from 100 W to 1500 Watt need to be catching up to > >>> the old Collins tube Amps with negative feedback, producing - 45 dB or > >>> better IMD products. > >>> > >>> The military amplifier are fast on , reliable , durable and expensive... > >>> initially. > >>> > >>> The noisy blower may be a bad thing. > >>> > >>> I “only “ run 1 KW, and I am happy with it > >>> > >>> 73 de N1UL > >>> > >>> Sent from my iPhone > >>> > >>>> On Dec 12, 2018, at 10:47 AM, Bob kb8tq <[email protected] > >>>> <mailto:[email protected]>> wrote: > >>>> > >>>> Hi > >>>> > >>>> Usually on HF, the issue is large signal rejection. Phase noise very > >>>> definitely > >>>> gets into that part of things. Other components in the signal chain do > >>>> as well. > >>>> Once the synthesizer is no longer the weak link in the chain, spending > >>>> more > >>>> to improve it (vs spending on the other components) probably does not > >>>> make > >>>> a lot of sense. Since the synthesizer is *far* from ideal, that sort of > >>>> begs the > >>>> question of just how troublesome the other parts are and how much better > >>>> a > >>>> device *could* be built. > >>>> > >>>> This does seem to be wandering a bit from a Time related topic ….. > >>>> > >>>> It does illustrate the point that “good enough” may be way far away from > >>>> “pretty good” and yet even more distant from “as good as it gets”. The > >>>> question on any system is always “how good do you need / what are you > >>>> doing?” …. > >>>> > >>>> Bob > >>>> > >>>>> On Dec 12, 2018, at 8:49 AM, jimlux <[email protected] > >>>>> <mailto:[email protected]>> wrote: > >>>>> > >>>>> On 12/11/18 3:26 PM, Bob kb8tq wrote: > >>>>>> Hi > >>>>>> As I said, just how rational using these parts in a radio …. not at > >>>>>> all clear to me. > >>>>>> Back when I went to school, stuff that was this noisy was not in the > >>>>>> “greatest” category. > >>>>>> That was a *very* long time ago. > >>>>>> Oddly enough best performance synthesizers have gotten better. (as the > >>>>>> posted > >>>>>> presentations very clearly show). Just why a “high end” radio uses a > >>>>>> less than > >>>>>> ideal synthesizer likely relates more to cost (even at a price of > >>>>>> thousands of dollars) > >>>>>> than to anything else. > >>>>> > >>>>> Or "good enough" performance - driving to a 3 dB NF for a HF receiver > >>>>> while maintaining good strong signal performance is probably not worth > >>>>> it > >>>>> > >>>>> > >>>>>> Indeed cost also drives things like GPSDO’s and GPS modules. We often > >>>>>> are not > >>>>>> very eager to acknowledge that fact. > >>>>>> Bob > >>>>> > >>>>> _______________________________________________ > >>>>> time-nuts mailing list -- [email protected] > >>>>> <mailto:[email protected]> > >>>>> To unsubscribe, go to > >>>>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > >>>>> and follow the instructions there. > >>>> > >>>> > >>>> _______________________________________________ > >>>> time-nuts mailing list -- [email protected] > >>>> <mailto:[email protected]> > >>>> To unsubscribe, go to > >>>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > >>>> and follow the instructions there. > >>> > >>> > >>> _______________________________________________ > >>> time-nuts mailing list -- [email protected] > >>> <mailto:[email protected]> > >>> To unsubscribe, go to > >>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > >>> and follow the instructions there. > >> > >> > >> _______________________________________________ > >> time-nuts mailing list -- [email protected] > >> <mailto:[email protected]> > >> To unsubscribe, go to > >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > >> and follow the instructions there. > > > > > > _______________________________________________ > > time-nuts mailing list -- [email protected] > > <mailto:[email protected]> > > To unsubscribe, go to > > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > > and follow the instructions there. > > > > > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
