1. Home
  2. Electronics Design
  3. Intercom
  4. Page 3

Intercom

There are a lot of different possible systems. Some interesting ideas:

  1. The vehicle (or a carry on) provides the carrier and each headset synchronizes a PLL to it and transmits SSB or DSB-SC. Very like sitting around the table. =20
1.A. For carriers below 30 MHz you try setting your modulation in quadrature to the carrier for FM like capture affects.

  1. Each headset transmits on a different frequency to combiner radio in the vehicle (also may be carried on) and all headsets receive the same signal from the combiner, AM, FM, and PCM all work about the same. Also similar to being at the table.

  2. Digitize the audio and send it at high bit rate all on the same frequency, with time slots set by the master radio, and all headsets receive all streams and can selectively combine them. This offers multiple one on one conversations at the same time. And other selective link possibilities.

What do you want the system to do?

?-)

Reply to
josephkk
Loading thread data ...

I think he wants to "roll his own" so that he can control the system properties. He might fine this page useful:

formatting link

Lots of vendors. Well maybe when the page was new.

?-)

Reply to
josephkk

The beauty of the wireless phones is that Jim can connect everything up and test the concept for almost no money. A live test in his environment will reveal weaknesses that he can address in his real application 'way faster than he could possibly do otherwise.

--Winston

Reply to
Winston

No, it is a marketing thing. If I've got something to sell that nobody else makes I've got a captive market.

Jim

Reply to
RST Engineering

Yes, tons of DECT phones out there and a few chipset suppliers, but no hard design data that I've been able to dig out.

THanks,

Jim

Reply to
RST Engineering

NOW we are getting somewhere. Lots of dead links, as you said, but the few that are still hot are probably going to get me to where I want to go.

Thanks!!

Jim

Reply to
RST Engineering

Either (2) or (3) would probably work, but (2) is what I'll probably wind up with because I have the technology to do that quite easily.

Thanks,

Jim

Reply to
RST Engineering

OK now i will cop to my ulterior motive. If you make them maybe you = could sell me a set (at discount) for a different purpose (motorcycle).

Reply to
josephkk

I design such systems. If you are looking for solution, my contact is at the web site in the signature.

Vladimir Vassilevsky DSP and Mixed Signal Design Consultant

formatting link

Reply to
Vladimir Vassilevsky

I'll do it with one major caveat. Remember Heathkit? We do Heathkit for airplanes. You get a bag of parts and detailed instructions. AND you get to figure out how to make your headset mimic an aircraft headset. It isn't at all obvious how to do that.

Thanks,

Jim

Reply to
RST Engineering

Learnin' how to do it yourself is half the fun of engineering. It is just finding the information that is turning out to be a pain. Seems like everybody thinks we don't need data sheets or app notes to figure this stuff out.

Thanks,

Jim

Reply to
RST Engineering

could

Heathkit i can do. I started with Knight-Kit (some 50 years ago) which was similar. Do you remember them?

?-))

Reply to
josephkk

Knight-Kit T-150 was my first commercial amateur transmitter (I had already home-brewed half a dozen of them) and a Layfayette 6 meter receiver kit was my first commercial amateur receiver.

Jim

Reply to
RST Engineering

Ah the good old days. There was a surplus house in Mountain View where i could get 741s for 50 cents to $1. And Olson electronics and a = Layfayette store. Will call at Newark electronics.

:-)))

Reply to
josephkk

Do these have to be wireless? Just provide a jack at each seat and let everyone plug in. Provide a toggle switch at each location to switch from the entertainment channel to intercom.

--
Paul Hovnanian     mailto:Paul@Hovnanian.com
------------------------------------------------------------------
In theory, practice and theory are the same, but in practice they 
are different -- Larry McVoy
Reply to
Paul Hovnanian P.E.

(...)

Haltek! Heaven!

Santa Clara on the ECR! Who could forget Olson!

I don't remember a Lafayette store in the Gulch.

Remember the Heathkit store in Palo Alto?

--Winston

Reply to
Winston

The was a Lafayette Store in Scollay Squa-a-a-are in Boston, right in the middle of the red light district and burlesque houses ;-) ...Jim Thompson

[On the Road, in New York] 
--
| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |
             
I love to cook with wine.     Sometimes I even put it in the food.
Reply to
Jim Thompson

Scollay Square is on Beacon St. a hundred feet or so from the state house, and about a thousand feet from the old red light district. The red light district used to be called the combat zone, but I don't think there's much left of it...

Reply to
JW

Probably not. I'm talking from experiences 50-54 years ago when I was a student at MIT ;-) ...Jim Thompson

[On the Road, in New York] 
--
| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |
             
I love to cook with wine.     Sometimes I even put it in the food.
Reply to
Jim Thompson

Burstein Applebee fer sure.

--
Many thanks,

Don Lancaster                          voice phone: (928)428-4073
Synergetics   3860 West First Street   Box 809 Thatcher, AZ 85552
rss: http://www.tinaja.com/whtnu.xml   email: don@tinaja.com

Please visit my GURU's LAIR web site at http://www.tinaja.com
Reply to
Don Lancaster

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.