[Premium-Rx] R&S PR100 IQ demodulation mode?

[Clemens Paul]

Matt,

there are some digital IQ modulation modes in use also refererred to as QAM.
E.g. DVB-T and DVB-S use QAM.
I guess that such a mode can be demodulated (->audio) in the "IQ demod mode".
After the demodulator I would not expect analog audio (except in the
path to the speaker) as R&S calls it *digital* audio.

73
Clemens
DL4RAJ

----- Original Message ----- 
From: "Matt Blaze" <matt at crypto.com>
To: "Clemens Paul" <cpaul at gmx.net>
Cc: <Premium-Rx at mailman.qth.net>
Sent: Tuesday, February 21, 2012 12:29 AM
Subject: Re: [Premium-Rx] R&S PR100 IQ demodulation mode?



On Feb 20, 2012, at 4:14 PM, Clemens Paul wrote:

> The PR100 product brochure
>
> http://www.rohde-schwarz.us/file/PR100_bro_en.pdf
>
> on page 20 helps.
> Both I/Q data and digital audio are post agc/mgc.
> The block diagram also clearly shows that the "digital audio" (with
> 12,5kHz BW)
> comes out of the demodulator stage and you can choose to convert it by
> the internal D/A stage (->loudspeaker) or by an external DAC.
> So the digital audio is the result of demodulating the the raw I/Q
> data.
> Following the description in the brochure it is one of the following
> types:
> AM,FM,USB,LSB,ISB,PULSE,CW.
> The brochure says nothing about an "additional IQ mode" in the
> demodulator signal path.
> As there is ISB available you have to have two independent audio
> channels.
>

Clemens,

Yeah, the lack of any mention of the existence of the IQ demod mode in either 
the brochure or the manual is definitely making this harder than it needs to be!

Other than a few nits, by the way, I'm really liking the PR100.  It's definitely 
the best "all around" portable receiver / analyzer I've ever used.

The form factor takes some getting used to with the main tuning knob on the top, 
etc,  but this actually works reasonably well in practice.  Much lighter than 
it's predecessor EB200, too.

My biggest complaints so far are poor internal speaker audio (true of every R&S 
I've ever used) and an inexcusably noisy switching power supply / charger that 
renders it all but useless for analyzing weak signals below about 200 MHz using 
AC power.  But otherwise, quite nice.

-matt



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