[opendtv] Re: New Microtune tuner
- From: "Allen Le Roy Limberg" <allimberg@xxxxxxxxxxxx>
- To: <opendtv@xxxxxxxxxxxxx>
- Date: Sat, 4 Mar 2006 12:36:54 -0500
Double conversion is useful in OTA DTV receivers for eliminating image
frequencies when the second intermediate frequency is below 45 MHz or so. A
10.76 or 21.52 kHz 2nd IF carrier frequency is convenient when using the
analog-to-digital converter circuitry to recover baseband DTV signal
directly. See U. S. patent No. 6,118,499 to Fang, for example. Or when
synchrodyning is done in the digital regime. See U. S. patent No. 5,606,579
to C. B. Patel and yours truly. As I recall, U. S. patent No. 5,809,088 to
Han Dong-Seog describes the digital synchrodyning done by Costas loop.
Al Limberg
----- Original Message -----
From: "Richard Hollandsworth" <holl_ands@xxxxxxxxx>
To: <opendtv@xxxxxxxxxxxxx>
Sent: Friday, March 03, 2006 12:01 AM
Subject: [opendtv] Re: New Microtune tuner
> 1. So why is there a 2 dB improvement in Noise Figure between Cable and
OTA mode? Narrower frequency range....or maybe OTA mode was configured for
single conversion???
> 2. Benchmark doesn't say anything about how results were obtained....only
useful information seems to be that they exceeded A/74 by one or two dB.
>
> 3. Double conversion tuners are frequently used for cable application,
since the complex multi-band tunable bandpass filters on the input of a
single conversion tuner can be replaced by a single fixed frequency BPF
filter at the first IF freq.
> But this would mean that wideband, high level signals go directly into the
first RF Amplifier stage, just like a Preamp. RF AGC will reduce the gain
of this stage, but it will be based on the strongest signal anywhere in the
bandwidth of the receiver, rather than the much narrower (10-20 MHz)
bandwidth of a conventional single conversion tuner with input RF BPF.
>
> The best of both worlds would employ tunable RF BPF's prior to the first
RF Amp stage...which would further degrade the overall mediocre Noise Figure
of the more complex double conversion tuner.
>
> Too bad they didn't also post a Reference Design with detailed schematics
and performance numbers...
>
> PS: It didn't explicitly state whether it only supports 6 MHz spacing for
local oscillator PLL frequency....maybe it supports other frequency
spacings....and maybe it doesn't...
>
> <holl_ands>
>
> ===================================
> John Golitsis <john@xxxxxxxxxxxxxxxxxx> wrote: Until they fix their web
site:
>
> Product Brief:
> http://www.microtune.com/products/pdf/mt2131_tuner_ic.pdf
>
> In the News:
> http://www.microtune.com/news/2006Articles
>
> Benchmarks
> http://www.microtune.com/products/pdf/mt2131_benchmarks.pdf
>
>
> On 2-Mar-06, at 3:41 PM, Dale Kelly wrote:
>
> > This may be good news.
> > Low-cost 3-in-1 TV tuner chip debuts
> > > broadcastengi
> > neering.com/newsletters/rfupdate/20060302/Microtune-MicroTuner-=20
> > MT2131-200603
> > 02>
> > Mar 2, 2006 8:00 AM, RF Update e-newsletter
> >
> > Microtune unveiled a three-in-one TV tuner Feb. 27 intended to =20
> > drive digital
> > TV reception into the cost-sensitive consumer TV mass market.
> > Integrating three tuners =97 analog, digital and cable =97 in a chip
=20=
>
> > smaller
> > than a thumbtack, Microtune's new MicroTuner MT2131 tuner delivers
> > performance that exceeds all three existing U.S. TV requirements: =20
> > ATSC, NTSC
> > and Digital Cable Ready (DCR), according to the company.
> > Eliminating more than 100 components from the silicon tuner bill of
> > materials, BOM, the MT2131 cuts external BOM cost by 60 percent. By =20=
>
> > breaking
> > through the sub-$3 cost barrier, it enables manufacturers to deploy =20=
>
> > a tuner
> > across all TV models, sizes and price points.
> > Microtune has published its internal benchmark tests of the MT2131 =20
> > and a
> > comparison of the MT2131 to the measurement test results of the =20
> > FCC's study.
> > For more information, visit www.microtune.com
> > > www.microtune
> > .com> .
>
>
>
>
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