[Premium-Rx] The new R&S EM510 Direct-Sampling HF Receiver

[Adam Farson]

Hi Clemens,

That is astounding - a 24-bit ADC clocked at 64 or 66 MHz, and sampling a 3
to 10 MHz band slice!

In a 24-bit ADC with ENOB = 20 (for example),  the theoretical margin
between the noise floor and the "all 1's" point is 120 dB. Assuming a 30 dB
process gain in the DDC following the ADC, this leads to a theoretical
dynamic range of 150 dB for a 3 MHz-wide RF sample window and a 3 kHz-wide
baseband.

The ADC's SFDR will now be the limiting factor in the DR performance of the
EM510. I wonder what SFDR values will be achievable with this fast 24-bit
ADC.

Cheers for now, 73,
Adam VA7OJ/AB4OJ


-----Original Message-----
From: premium-rx-bounces at mailman.qth.net
[mailto:premium-rx-bounces at mailman.qth.net] On Behalf Of Clemens Paul
Sent: 25 February 2007 02:55
To: premium-rx at mailman.qth.net
Subject: Re: [Premium-Rx] The new R&S EM510 Direct-Sampling HF Receiver

Interesting addendum about the ADC.
Contrary to the brochure all EM510 of the series production use a 24bit ADC.

73
Clemens
DL4RAJ
----- Original Message -----
From: Clemens Paul
To: premium-rx at mailman.qth.net
Sent: Sunday, February 18, 2007 8:32 PM
Subject: Re: [Premium-Rx] The new R&S EM510 Direct-Sampling HF Receiver


>... the phase noise is that of a single crystal oscillator at circa 100 
>MHz.  (Or the ADC's inherent process noise, which I imagine is a bit 
>worse.)
>-- john, KE5FX

According to the R&S engineers the phase noise comes mainly from the ADC
clock while the aperture jitter of the ADC adds only little phase noise.

R&S uses an ADC from Analog Devices with a sampling rate of around 80MHz.

Maybe it might be custom designed because there have been meetings between
top engineers 
>from R&S and Analog Devices during the development.
But that's speculation.

Clemens

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