[opendtv] Re: New Microtune tuner

  • From: "Dale Kelly" <dalekelly@xxxxxxxxxxx>
  • To: <opendtv@xxxxxxxxxxxxx>
  • Date: Thu, 02 Mar 2006 15:34:05 -0800

The double conversion feature is a good start and will certainly help with
IM issues and I agree that the high signal in band stations Mark Aitken
mentions will likely require some RF selectivity and properly implemented
agc to deal with this issue.

As I recall, the Miami area is a good example of the signal condition
mentioned by Mark..

-----Original Message-----
From: opendtv-bounce@xxxxxxxxxxxxx [mailto:opendtv-bounce@xxxxxxxxxxxxx]On
Behalf Of Manfredi, Albert E
Sent: Thursday, March 02, 2006 3:04 PM
To: opendtv@xxxxxxxxxxxxx
Subject: [opendtv] Re: New Microtune tuner

Dale Kelly wrote:

> Mark Aitken wrote:
>> If it works in strong multi-channel/signal environments
>> without overload. ATSC A/74 does not cover the real needs
>> in this area, and was a subject of much discussion.
>
> Mark, you are correct of course, thanks for the reminder.
> I now recall my frustration over that issue.

This Microtune tuner is a dual-conversion design.

If I'm not mistaken, our (my) best guess as to what's needed for the
more difficult cases, such as Mark Schubin's apartment with antenna away
from window, would be either a dual-conversion tuner with additional
tuned RF amp up front, or a single conversion tuner, with tuned RF amp,
and with some extra image cancellation in the IF stage.

That article we discussed from Digital TV Design Line:

http://www.digitaltvdesignline.com/howto/settopboxdesign/173601582;jsess
ionid=3DQSILQWCRREW1UQSNDBECKHSCJUMEKJVN

(good luck with the link)

took the latter approach. To a single-conversion IF, they an additional
"active image cancellation" in the mixed oscillator PLL stage.

In that article, they say that dual conversion tuners do not typically
include a tuned front end AGC. If that's the case, then possibly this
tuner will require "window placement" of the antenna in Mark's
apartment. That's a guess.

Even so, in somewhat less demanding venues, being A/74 compliant, they
would doubtless be better than the 3rd gen stuff we often are made to
get by with now.

Also, this tuner is likely a 6 MHz only bandbass, because it's only
designed for NSTC, ATSC, and cable. So Jeroen won't be able to use it in
his new all-standards DVDR/PVR he's cooking up for us.

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.


 
 
----------------------------------------------------------------------
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: