[time-nuts] Modern signal generators

[Magnus Danielson]

Hi Ulrich,

Analog/Hitite
https://eu.mouser.com/new/hittite-microwave/hittite-hmc832-pll/

Cheers,
Magnus


On 12/12/18 9:44 PM, Ulrich Rohde via time-nuts wrote:
> Who makes it ?
>  
> In a message dated 12/12/2018 3:43:23 PM Eastern Standard Time, richard at karlquist.com 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 <kb8tq at n1k.org> 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 <time-nuts at lists.febo.com> 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 <kb8tq at n1k.org> 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 <jimlux at earthlink.net> 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
>>>>>>
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>>>>>
>>>>>
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