13 novembre 2008

Sony XDR-F1HD/DSP, migliore radio FM di sempre?

La comunità degli appassionati di ascolto FM a lunga distanza è in subbuglio dopo l'uscita di un "tuner" per la radio analogica e digitale (il sistema è HD Radio, che in Europa praticamente non esiste a meno di qualche sparuto test) della Sony, modello XDR-F1HD. Tutti fanno a gara per procurarsi una radio che sembra funzionare splendidamente anche (soprattutto, direi) per le emittenti analogiche. L'apparecchio è un vero e proprio sintonizzatore, richiede cioè l'amplificazione audio. Ma ha due virtù che lo rendono imbattibile. Costa meno di cento dollari negli USA, ma anche con le spese di spedizione e dogana si tratta di una somma più che abbordabile. Ed è basato su sofisticati chipset di NXP che implementano un filtro IF digitale (DSP), il quale funziona come una bomba nel rimuovere le interferenze dai canali adiacenti. L'inconveniente dal nostro punto di vista è che il passo di sintonia di 100 kHz non tiene conto del totale menefreghismo delle stazioni italiane, che non hanno mai rispettato canalizzazioni e soglie di guardia fissate dall'Europa. Ma i risultati sono lo stesso di grande impatto, come si può vedere e sentire da questo breve filmato su YouTube



o negli spezzoni audio che trovate in questo forum di discussione del club di FM-DXer WTFDA.
Accludo qui la recensione apparsa su The.Street ma vi consiglio di scaricare subito, prima che la URL finisca nella palude stigia di Internet l'articolo di Bryan Beezley su Ham-radio.com, con plot e una quantità di modifiche pensate per le esigenze dei DXer. Potetei procuravi qui un'altra recensione molto tecnica. E qui trovate la pagina dell'XDR sullo online shop di Sony USA
Per approfondire gli aspetti più intimi di questo interessante ricevitore ecco il datasheet e una application note per il front end che produce la IF digitale (il TEF-6730), mentre su questi manuali Philips ci sono altre informazioni (manuale 1 e manuale 2) sui chip DSP di backend , le famiglie SAF773x e SAF778x. Qui in questo comunicato iBiquity ci sono altri dettagli sui componenti NXP all'interno dei ricevitori HD Radio di seconda generazione, basato sul modulo UMA-H3 che comunica con gli NXP Digital Signal Processors modelli SAA7724, SAF7730 e SAF7780 attraverso l'interfaccia seriale standard I2C supportando gli NXP "Dice Tuners" (il tuner RF su singolo chip) modelli TEF6700, TEF6721 e TEF6730 (più lo guardo e più mi piace, dal punto di vista ingegneristico il sistema ibrido HD Radio).
Vi metto qui anche gli schemi funzionali del TEF6730 e del SAF7780/DSP.
















Sony HD Radio Tuner Hits All Right Notes
Gary Krakow 11/11/08

You want one of these and you might realize it yet. Want to know why? Because it just might be the best ever made.
I'm talking about Sony's(SNE Quote - Cramer on SNE - Stock Picks) XDR-F1HD AM/FM/HD Radio tuner. This is a radio tuner. That means you have to plug it into a hi-fi or home theater setup to listen. It receives local AM and FM stations as well as all the new HD channels.
HD is the new digital method for U.S. broadcasters to deliver over-the-airwaves audio and data in addition to their analog signal. If radio stations choose to broadcast in HD, they can add one, two or more digital channels on the same frequency as their analog station.


Best Tuner Ever?

On the FM band, the first HD channel is usually a digital version of the regular analog station. Other digital channels, by law, must provide separate and varied programming. AM stations use an HD signal to rebroadcast a digital version of their regular signal. Listening to HD radio is free (unlike XM/Sirius (XMSR Quote - Cramer on XMSR - Stock Picks) satellite radio). All you need is a new tuner.
If you live in an area with few radio stations, this Sony tuner probably won't do much for you. On the other hand, if you live in, around or near a large urban area, such as New York City or another area with a large selection of FM stations, then you should be interested. Despite a few email complaints I sometimes receive concerning "Nothing good to listen to on radio so why bother?" I believe that these new, over-the-air digital music streams can, and in some cases do, provide terrific sounding, commercial-free music worth listening to.
I've written about HD radio tuners before. Models from Sangean, Rotel and DaySequerra range from $200 to $1,700 and all provide, to varying degrees, very good to excellent sound quality. The DaySequerra sounds the best to my ears. Then again, David Day makes all the professional HD tuners used by radio station engineers to monitor their signals.
That's why I was intrigued after hearing about this new Sony model. According to experts, this tuner measures better than just about any radio tuner ever made. Although very technical and thorough, read the test results from tuner expert Brian Beezley. I won't give away everything he says except for one quote: "The performance of the Sony XDR-F1HD on stereo FM is spectacular and unprecedented." He not even talking about how well it does with HD stations. He means the Sony's analog reception of stereo FM stations is amazing.
The box itself is small, compact and lightweight, almost in-dash car radio sized. There's an on-off switch on the front, next to the large display window. There are some buttons on the top, but it's easier to control everything from the included remote control. There are separate wire AM and FM antennas included in the box. RCA output jacks allow you to attach the XDR-F1HD to your stereo.
So we know how it measures, but how does it sound? Amazingly good in my system. Let me qualify that. It's not as good as the best, big-bucks FM tuners I've ever heard but extremely good nonetheless. On AM, the sound is excellent. AM HD makes all-news and all-talk stations sound fabulous.
Notice, I have yet to mention price. That's because I like leaving the best for last. This amazing AM/FM/HD tuner retails for less than $100. Do a little search on the Internet and you can find it selling for less than $80. I'm not kidding, one of the best FM tuners ever measured sells for a pittance compared to the best tuners of the past.
If you're at all interested in what HD radio sounds like and can provide, this is not only an inexpensive way to find out but it may also be one of the best. To my way of thinking, this is the ultimate holiday gift for any audiophile or radio lover on your shopping list.
One last thought. What would happen if you took the radio section of this Sony and combined it with better audio circuitry and an improved power supply? Would it be the best radio ever? I hope we'll find out soon.
This Sony tuner is very, very highly recommended. Unbelievably recommended for the price.


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