[opendtv] Re: New Microtune tuner
- From: Richard Hollandsworth <holl_ands@xxxxxxxxx>
- To: opendtv@xxxxxxxxxxxxx
- Date: Thu, 2 Mar 2006 21:01:54 -0800 (PST)
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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