i found in my electronics salvage an old ic its a TDA3845 when i searched for it and looked at the datasheet i saw that its
a Quasi split-sound circuit and AM demodulator .
so my question is :
1- what is Quasi split mean ??
2- i was wondering can i use it to make an AM or FM radio or something ?
i saw a circuit for the ic and its seems very simple
so what exactly is it (it seems more like a radio to me ) ?
1- what is Quasi split mean ??
Quasi Split Sound is a way of describing the NICAM stereo transmission system.
From Wikipedia:
Near Instantaneous Companded Audio Multiplex (NICAM) is an early form of lossy compression for digital audio. It was originally developed in the early 1970s for point-to-point links within broadcasting networks.[1] In the 1980s, broadcasters began to use NICAM compression for transmissions of stereo TV sound to the public.
so the ic was designed to receive NICAM packet audio transmission for the tv ?
so most of the tv audio transmisstion is NICAM ? and is there a radio broadcasts using the same protocol ? can i use that to receive tv brodcasts (the sound only ) ?
and how i will modify it to receive AM ?
so i have to make a local oscillator and mixer circuit to produce the IF then feed it to the ic
and change the LC thank circuit for AM ?or what
sorry i have a lot of questions , i realy appreciate your help
In the UK, analogue UHF TV had nicam stereo sound.
The basic TV sound signal was FM, the nicam part made it into stereo for receivers which were equipped to decode it.
All UK TV is now digital, the analogue and NICAM are gone.
iam sorry i thought you ment the circuit above .
actualy i connected an internal (oscillator - mixer - IF amp ) from another ic i have to the TDA3845 theoreticly it should work
but it didnt i heared just a hissing sound !?
iam sorry but why my previos comment has changed i dindt mean any thing just was asking !?
I don't really see why you're playing with this chip, it's NOT a radio chip, it's a TV one.
It 'might' be possible to use some parts of it to help build a radio?, but it's likely to be pretty difficult as there won't be any data out there about doing so.
I don't really see why you're playing with this chip, it's NOT a radio chip, it's a TV one.
It 'might' be possible to use some parts of it to help build a radio?, but it's likely to be pretty difficult as there won't be any data out there about doing so.
me :can i use that to receive tv brodcasts (the sound only ) ?
JimB: Yes, I think so.
"i think so " from JimB , gave me a little motivation to try the circuit , but no problem ( building and experimenting with radio circuit is one of my true passions )
But, you have to use all the appropriate parts:
Signal frequency tuned circuits and an RF amplifier to give the required sensitivity.
A mixer and local oscillator to convert the signal frequency to the intermediate frequency.
A suitable IF filter to give the required selectivity.
An audio amplifier to give enough power to drive the loudspeaker.
But, you have to use all the appropriate parts:
Signal frequency tuned circuits and an RF amplifier to give the required sensitivity.
A mixer and local oscillator to convert the signal frequency to the intermediate frequency.
A suitable IF filter to give the required selectivity.
An audio amplifier to give enough power to drive the loudspeaker.
It does not, I never said that it would.
Have a look at post #4 of this thread for my best attempts to give a positive/definitive reply to the OPs questions which may have lead to some experimentation for him, rather than a wet blanket "Oooh, you can't do that!" kind of reply.