> Panasonic has a feature in some of its car receivers called
> "Radio DSP." What exactly is it? It claims to reduce
> adjacent channel interference and multipath distortion.
> Does it have something like SSB/ECSS on the AM side?
>
If it's anything like what's in the Pioneer and Blaupunkt radios, it is a digital front end which manipulates the bandwidth of the receiver based on conditions. Sounds good, right? Well, it increases selectivity with two tradeoffs
1) Distortion is very high
2) Sensitivity seems to suffer a bit
Blaupunk claims 6dBf (usable) decibel femtowatts.. it acts more like 17dBf . Big difference.
Pioneer claims 8dBf (usable). It's probably a bit overrated as well, although I don't remember sensitivity being as bad as the Blau.
As a rule, Don't touch anything that doesn't yield better than 17dBf stereo // 12dBf usable for sensitivity.. lower numbers are better. Also, try and compare different models from each brand. Look for a brand that has the same tuner spec across the board. You're most likely getting their best design, even in the cheaper models.
The Blaupunkt gives you the option to turn it on or off. The Pioneer does not. The Blaupunkt also gives you the option of turning off the high blend circuit. Pioneer doesn't, thus, the Pioneer is distorted and dull sounding MOST of the time. Both the Pioneer and Blaupunkts fall back to mono long before they really need to.
If the Panasonic is anything like these two, forget it. It's not worth the raised distortion level and sensitivity loss. Get a Clarion (17dBf stereo // 11dBf usable) or an Eclipse (13 dBf stereo // 10dBf usable). Both have much better than average selectivity, the Clarion has no blend circuit for the highs (it does go to mono) and the Eclipse has no high blend *OR* mono blend (in stereo, even under poor signal conditions, the noise floor is much lower than one would expect... Eclipse did an excellent job).
With the Pioneer and Blaupunkt, you may end up with 5 extra miles of coverage in first adjacent shoehorn situations, but it's not worth putting up with the decreased sound quality.
FWIW: Sony (9 dBf usable) also has a digital front end, but they don't use it for increased selectivity (Sony radios are still behind in the selctivity department). The goal is decreased multipath. However, the result is the same distorted audio, which usually happens with co-channels or on the fringes, or in multipath areas (HAHA!) just where you would want the "innovative" technology to help. Yeah, you don't get the spitting and hashing of multipath, instead you get distortion. Is there much of a difference???
P.S. With the digital front end, I wonder if Panasonic fixed their AM problems. Their most recent models had HORRIBLE upper sideband selectivity and were prone to all sorts of noise and hum from power lines, signs, car alarms, traffic signals. You couldn't even drive side streets listening to locals, all you heard was CONSTANT hum under the audio within 100 feet of ANY power line. Also, music stations with bass would cause the AGC circuit to lose its mind.
