On 28/10/2020 17:29, Max Demian wrote:
On 28/10/2020 16:36, Dave Plowman (News) wrote:
In article ,
Â*Â*Â* Martin Brown wrote:
I have a Denon mini hifi system upstairs in my computer room/office
and a 20? YO Phillips cassette/radio in the kitchen. If both are on
and tuned to the same BBC FM channel I can hear that they are out
of sync for some reason.

Are you sure one of them isn't on DAB or using a DAB digital tuner of
some sort for FM reception which introduces an interesting delay on
programme content (as well as being highly inefficient).

No audible delay between any FM tuners I've ever heard. But may well be
within the computer, which likely changes the analogue to digital and
then
back to analogue for its speakers.

Roberts Play using FM has a bit of an echo with other (frequency
synthesiser type) FM radios.

Motorola smart phone FM radio function has a delay of about 1/3 second.
So there must be some digital processing, even with FM.

(DAB is about 3 seconds behind.)

I think it is because the implementation of FM reception on some modern
tuners is entirely digital as software defined DSP radio implementation
rather than a classical analogue circuit (where delay is negligible).

Tuners sold as DAB tend to have this problem more than most. It
manifests as curious flanging effects as you move between the sound
fields of different radio receivers. It wouldn't surprise me if mobile
phones used a software solution for FM reception.

Different DAB tuners show it much more profoundly.

--
Regards,
Martin Brown