2 radios, side by side, same station, signal delay?!?

[Foggy]

Why? How is that possible?
Same Brand, different models, one is new, the other is 20yrs old.

740 AM news radio, KCBS

[Machine_Elf]

Maybe the new one has some digital signal processing going on that results in a slight delay? Can you tell which unit is behind the times, and which one is ahead?

[whitetho]

This is a real long-shot, because very few AM receivers are HD capable, but the newer receiver could be picking up the station’s HD signal, which is transmitted along with the normal signal, but only after a short delay due to some processing that is needed to encode it.

[Weisshund]

radio is not a magical route from antenna to speaker

the radio signal is picked up, it is processed, it is converted to audio then fed to an amplifier circuit then into the speaker.
(probably not perfect description)

This takes time, and takes different amounts of time depending on the electronics.
If you want close to 0 delay, use a crystal set radio

[Foggy]

These are cheap radios from Jensen. The new one is delayed by several seconds.

The old one has weather bands. On battery power.

The new one has a CD & Cassette player. Is on AC power.

[Machine_Elf]

@Foggy

The new one is delayed by several seconds.

several seconds? Like enough time to count “One Mississippi, two Mississippi, three Mississippi…”? :eek:

Is it one of those fancy radios that lets you adjust a deliberate delay so that you can sync the audio with what’s happening on TV?

@SportSync Radio

Radio play-by-play announcers provide the most descriptive, interesting and fun calls of pro or college sports events. But radio signals almost always run several seconds ahead of TV broadcasts which must pass through cable, satellite or HDTV systems. Before, if you tried to listen on the radio and watch on TV, you heard each play called on the radio well in advance of the same action you saw on TV….it took all the fun out of the game. Now, with the SportSync SR-303, you can delay the radio audio up to 16 seconds to exactly match what you’re watching on TV.

[Amateur_Barbarian]

I’d guess as above - the older radio is a simple analog tuner, while the new one is chip-based and the chip’s digital massaging of the signal adds a second or two of delay.

[joema]

@Machine_Elf

Maybe the new one has some digital signal processing going on that results in a slight delay? Can you tell which unit is behind the times, and which one is ahead?

That is the most likely explanation. Modern radios increasingly use digital signal processing (DSP) either for audio or the entire signal chain. There are AM/FM radios on a single chip which reduces the parts count and manufacturing cost, even for low-end consumer devices.

Using DSP entails latency. Digital signal processing is a tradeoff of latency vs filter quality. The design of a consumer broadcast receiver using DSP would not prioritize low latency, so it’s possible there could be significant delay.

It is now possible to design cable TV receivers which use only software for demodulation and signal processing: https://www.youtube.com/watch?v=sspSh7o3x_A

[Foggy]

@Machine_Elf

several seconds? Like enough time to count “One Mississippi, two Mississippi, three Mississippi…”? :eek:

about 5 Mississippi

Is it one of those fancy radios that lets you adjust a deliberate delay so that you can sync the audio with what’s happening on TV?

No

@joema

Using DSP entails latency. Digital signal processing is a tradeoff of latency vs filter quality. The design of a consumer broadcast receiver using DSP would not prioritize low latency, so it’s possible there could be significant delay.

Thanks:)