In article <h2cmf5$49k$6@news.albasani.net>, The Natural Philosopher
<tnp@invalid.invalid> scribeth thus
>tony sayer wrote:
>> In article <2ee3287350.davehigton@dsl.pipex.com>, Dave Higton
>> <davehigton@dsl.pipex.com> scribeth thus
>>> In message <VA.00000751.00af3130@escapetime.removethisbit.myz en.co.uk>
>>> Roderick Stewart <rjfs@escapetime.removethisbit.myzen.co.uk> wrote:
>>>
>>>> In article <ba9c9e7150.davehigton@dsl.pipex.com>, Dave Higton wrote:
>>>>> I /do/ understand the technologies involved. FM is worse than DAB
>>>>> because all the decoders we use are non-linear, therefore FM
>>>>> broadcasts, once received, are subject to intermodulation and
>>>>> harmonic distortions. DAB isn't. It is very much like the vinyl
>>>>> versus CD and valves versus transistors arguments.
>>>> My apologies for repeating myself, but this silly argument seems to
>>>> have been repeated a few times and needs nailing down.
>>>>
>>>> Saying that a comparison between FM and DAB is like a comparison
>>>> between vinyl and CD is nuts. DAB uses destructive digital bit-rate
>>>> reduction; CD doesn't. CD audio is sampled at more than twice the
>>>> highest frequency most people can hear, with enough bits to give a
>>>> dynamic range greater than any mechanical gramophone system and
>>>> certainly well beyond that of a typical living room, and then no
>>>> information is thrown away. None at all. It's better than FM, better
>>>> than gramophone records, better than tape cassetes, and it stays that
>>>> way all the way to the customer.
>>>>
>>>> The main criticisam of DAB is that information *is* thrown away in such
>>>> a manner that it can never be completely recovered, not even
>>>> theoretically, and this is done by the broadcasters themselves before
>>>> the signal even gets to the transmitter.
>>> Yes, it's thrown away. But it doesn't necessarily result in a
>>> reduction of quality, which is all down to perception.
>>>
>>> You appear to be avoiding my point that FM, being analogue and
>>> being demodulated by a system that is non-linear, inevitably
>>> introduces non-linear distortions: intermodulation and harmonic
>>> distortion, to the audio. The DAB system can be engineered so
>>> that the non-linearities are arbitrarily small, perhaps just a
>>> few parts per million.
>>>
>>> Dave
>>
>> Yes of course the DAB system should be better, how many bits do you
>> think it needs in practice?..
>>
>> Mind you good FM demod systems don't have -that- much distortion..
>
>No. 0.1% mono and 0.3% stereo was what I got with the RCA chipset. In 1975.
>

Its improved a bit since then .. 'tho the bits have dropped
otherwise;!..
--
Tony Sayer