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

Sun Feb 18 03:44:09 EST 2007

Peter,

thanks for that clarification about ARRL's wrong test methods regarding the SDR-14.
So there remains a difference of 10dB in DR3 between the SDR14 and the EM510.
The the price difference  for the basic receiver is about in the same order of magnitude
than in the 80's beteeen an amateur trx and a say E1800.
But those last 10dB in DR3 make the difference between common and state of the art
receivers (comparing the same technology) and always used to be as extremely expensive as now.
I think R&S just ask the price  which they think to be competitive in the professional market.
And to my knowledge the EM510 sells extremely well.
Most of us will (have to) prefer to wait for affordable prices for >100dB DR when the ADC-
technology makes further progress.

I wonder why nobody seems to have made notice about the close in phase noise of 140dBc/Hz
at 1kHz.
That means a reciprocal mixing noise of 113dB down in a 500Hz BW at 1kHz.
Therefore, when it comes to close in DR,IM3- or noise limited, the EM510 is substantially
better than any amateur or professional rx I know (including the EK895) on the market
because here phase noise sets the limit for DR (exception Orion2: 95dB DR is IM3 limited).

73
Clemens
DL4RAJ

----- Original Message ----- 
From: Pieter Ibelings
To: cpaul at gmx.net ; premium-rx at mailman.qth.net
Sent: Sunday, February 18, 2007 3:39 AM
Subject: Re: [Premium-Rx] The new R&S EM510 Direct-Sampling HF Receiver

Paul,

The 34dB DR3 of the SDR-14 sounds absurd, because it is. The ARRL had no
clue what they were doing. When they measured the IP3 they extrapolated a
very small spur at low levels and assumed it was a 3rd order product. They
did not even notice that as they increased the level of the two carriers,
the spur that they though was a 3rd order product would not change. That is
why they came up with an absurd IP3 number of -15dBm to +29dBm. The ADC used
in the SDR-14 (AD6644) has pretty good performance. If you insert two tones
at -2dBm, the third order products are still lower than -95dBc.
The EM510 is a much more complex radio than the SDR-14, but it is also 30-40
times the cost. If you tried the SDR-14, you would see that the performance
is a lot better than you think. I have been using one for about 3 years,
almost every day.

Best Regards,

Pieter, N4IP

>The SDR-14 has a DR3 of *34*dB for 500HZ BW (ARRL) which sounds absurd
>(like the whole comparison) compared to 105dB.
>The EM510 can process realtime I/Q data with a BW of 10MHz, the SDR14
>max.150kHz.
>The ADC of the SDR14 overloads at -23dBm,the EM510's IP3 is tested with
>2x-7dBm.
>The EM510 is fully LAN controllable.
>It's also interesting to have a look at the filter specs (there are none
>with the SDR-14).
>There seems indeed  to be a bit more than the price and the R&S logo on the
>case
>(as someone said here on the list), which makes the difference between a
>SDR14 and a EM510.
>The preamp of the EM510 delivers an output of +16dBm into the ADC with a
>SFDR of >96dB.
>It was not easy even for the R&S engineers to design such a preamp.
>So there's a LOT more than buying an off the shelf  16bit ADC to design a
>digital radio with
>those specs.
>And therefore I think the whole package inside the case IS exciting.
>
>73
>Clemens
>DL4RAJ
>
>
>
>
>
>---Original Message-----
>From: sig346 at netscape.net
>To: farson at shaw.ca; Premium-Rx at mailman.qth.net
>Sent: Thu, 15 Feb 2007 10:01 PM
>Subject: Re: [Premium-Rx] The new R&S EM510 Direct-Sampling HF Receiver
>
>    The RS Datasheet reveals potentially weakness of all Direct Sampling
>HF Receivers: their limited
>  dynamic range. To hide this RS tries stretching both German and
>English languages . As a result,
>  a new wording has been invented: LOW DISTORTION MODE. In this mode,
>which actually is nothing
>  more than an attenuator at the input, the receiver has IP3 of 30dBm,
>BUT NOISE FIGURE OF 26dB!.
>
>  I will send email to Rhode und Schwarz suggesting one more mode:
>ULTRALOW DISTORTION,
>  to obtain 50 dBm of IP3, but that would require 30dB attenuation,
>bringing noise froor to
>  45 dB. It would be, nevertheless, sufficient to listening to Deutsche
>Welle in the World Bavarian Capital of Munich.
>
>  Rockwell Collins describing their similar direct sampling receiver
>CX7800 simply "forgets" include some data
>  regarding dynamic range. That makes their life simpler: no need to
>hide an army of technical linguists.....
>
>  On a serious note, I tried CX7800. It is a respectable receiver, but
>far from being "Premium", not much
>  better than SDR14. So, you, gentlemen - owner of WJ, TCI, CUBIC,
>Telefunken, etc - remain cool -
>your receivers are still "Premium" without stretching imagination.
>
>Regards,
>AW
>
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