[opendtv] Re: White paper from CEA
- From: Richard Hollandsworth <holl_ands@xxxxxxxxx>
- To: opendtv@xxxxxxxxxxxxx
- Date: Fri, 4 Nov 2005 17:56:22 -0800 (PST)
FYI: Zarlink ZLE10568 is a multi-purpose TV, Open Cable and DVB-C Tuner that
happens to use a Double Conversion technique. Picture shows interior
components. If you hold a Type-F connector up for comparison, you'll see that
the 70mm x 55mm Tuner is roughly life size (3.25" x 2.25"):
http://assets.zarlink.com/PP/ZLE10568_Product_Preview_0505.pdf
The RF part of a Tuner isn't very expensive or very big (Tuned
BPF/Mixer-Osc/IF) plus a small controller chip to accept control info from STB.
The Infineon TUA6034T App Note [I recently posted the link] shows a somewhat
smaller Tuner (picture is smaller than life size, compare to size of IEC
connector). The App Note includes detailed block diagram, schematic, detailed
parts list and a complete set of specs.
Even smaller NTSC Tuners are available for your car....
And ATSC/DVB-T Tuners for laptops are finally being integrated...
Smaller usually means cheaper....esp with large quantities....
--------------------------------------
If you want a Dual Tuner, then simply double the components. They connect to
the same antenna, with an RF Splitter and 3-4 dB loss of sensitivity, just like
your Dual Tuner HDTV.
If you want to start with a Dual Tuner, Dual Diversity Smart Antenna, you're up
to four RF strips, two per antenna with same 3-4 dB loss of sensitivity, which
is more than made up by 3 dB antenna combining Gain and SNR improvement due to
suppresion of multipath and other interference. It would probably be no more
complex than what's currently in the $100 DX DTA-5000 Smart Antenna, which uses
a Quad Antenna Array. [See my posts in 5th Gen ATSC Receiver thread in
avsforum.com for pictures.]
A Hi-End, Dual Tuner, Quad Diversity Smart Antenna could be constructed with
eight RF strips, but a lower performing, lower cost alternative could be
constructed with only four RF strips that are allocated as neccessary,
depending on how many TV are active and which channel needs the most antennas
for combining purposes.
<holl_ands>
==================================
"Manfredi, Albert E" <albert.e.manfredi@xxxxxxxxxx> wrote:
Richard Hollandsworth wrote:
> If it's so easy and so obviously needed, why doesn't
> anyone make such a Preamp????
Seems to me that to design an RF amp that is tuned to
a specific frequency band, in tandem with the IF stage,
to improve selectivity, requires either that this
more expensive beast be incorporated in the receiver
itself (increasing cost) or that it be added as an
external device, used as needed. But such an external
device would then require a signal from the receiver.
If done as such an external device, it becomes
cumbersome or even unusable for any setup that
incorporates recording devices or multiple receiver
hookups of any type. Unless the multiple receivers are
contrained to receive the same channel at all times.
So bottom line, in my view, tuning a masthead or
similar external antenna amp is not the right way to
go.
Anything wrong with dual conversion tuners? They can
accept wide band RF amps without paying the
consequences. Or just build the fancy RF amp into the
receiver.
Bert
----------------------------------------------------------------------
You can UNSUBSCRIBE from the OpenDTV list in two ways:
- Using the UNSUBSCRIBE command in your user configuration settings at
FreeLists.org
- By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word
unsubscribe in the subject line.
---------------------------------
Yahoo! FareChase - Search multiple travel sites in one click.
----------------------------------------------------------------------
You can UNSUBSCRIBE from the OpenDTV list in two ways:
- Using the UNSUBSCRIBE command in your user configuration settings at
FreeLists.org
- By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word
unsubscribe in the subject line.
Other related posts:
