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Is there a dual NE567?

I'm currently designing a circuit with two NE567's(tone decoder PLL)
in it, so I'm wondering if there is an IC which contains two tone
decoders.

Thanks in advance

Ferdinand Meyer-Hermann
 
J

John Fields

Jan 1, 1970
0
I'm currently designing a circuit with two NE567's(tone decoder PLL)
in it, so I'm wondering if there is an IC which contains two tone
decoders.
 
The circuit is an intercom over a 2-wire interface. The goal is to be
able to use many stations on the same two wires and call them. My idea
was to superimpose an ultrasonic tone on the speech signal to do that.
So one NE567 is used to decode the tone and the other is used to make
it (a NE567 is a nice sawtooth oscillator with only two external
components). I could also use a 555 for this purpose, but combining
two NE567 would save a chip and an extra 555 would never save one.
Maybe there's a better way.
I haven't found any, but I could email the schematic to you. Maybe you
find the perfect solution...?

Ferdinand
 
J

John Fields

Jan 1, 1970
0
The circuit is an intercom over a 2-wire interface. The goal is to be
able to use many stations on the same two wires and call them. My idea
was to superimpose an ultrasonic tone on the speech signal to do that.
So one NE567 is used to decode the tone and the other is used to make
it (a NE567 is a nice sawtooth oscillator with only two external
components). I could also use a 555 for this purpose, but combining
two NE567 would save a chip and an extra 555 would never save one.
I haven't found any, but I could email the schematic to you. Maybe you
find the perfect solution...?

---
Maybe. ;)

In keeping with the spirit of the newsgroup, though, it would be
better if you posted it somewhere where we can all access it. Since
you can't access any of the binary USENET groups through Google that
rules out alt.binaries.schematics.electronic, but maybe you can post
it to a website somewhere and then post the URL here?
 
M

MooseFET

Jan 1, 1970
0
The circuit is an intercom over a 2-wire interface. The goal is to be
able to use many stations on the same two wires and call them. My idea
was to superimpose an ultrasonic tone on the speech signal to do that.
So one NE567 is used to decode the tone and the other is used to make
it (a NE567 is a nice sawtooth oscillator with only two external
components). I could also use a 555 for this purpose, but combining
two NE567 would save a chip and an extra 555 would never save one.> Maybe there's a better way.

I haven't found any, but I could email the schematic to you. Maybe you
find the perfect solution...?

I'm going to be the first in this thread with a "use a PIC" solution:

The PIC can read some dip-switches to know its station number. The
ADC can sample the signal from the two wires and code can look for
this stations frequency. The call signal can be a tone made by
wiggling a port output.


Now for a non-PIC based idea:

The LTC6906 makes a squarewave output with just a single resistor.
Changing the resistor value makes different frequencies for selecting
which station to call. The part is about as small as the capacitor
you'd need with any other sort of oscillator.

The decoding could be done by making basically a superhet radio. An
oscillator can be set just a small amount off the frequency for the
call signal and then a simple mixer could turn the call signal into a
tone in the audio band that is sent to the speaker to alert the user.
 
I'm going to be the first in this thread with a "use a PIC" solution:

The PIC can read some dip-switches to know its station number. The
ADC can sample the signal from the two wires and code can look for
this stations frequency. The call signal can be a tone made by
wiggling a port output.
This could be a solution kicking a bunch of electronics out of the
device. But it requires some modifications. See below...
Now for a non-PIC based idea:

The LTC6906 makes a squarewave output with just a single resistor.
Changing the resistor value makes different frequencies for selecting
which station to call. The part is about as small as the capacitor
you'd need with any other sort of oscillator.
I'd prefer the sawtooth generated by the NE567, because it has a lower
harmonic content. But, if I find a source of these, I'll consider
them.
Note that this is a hobbyist's project, so I need to buy in small
quantities.
The decoding could be done by making basically a superhet radio. An
oscillator can be set just a small amount off the frequency for the
call signal and then a simple mixer could turn the call signal into a
tone in the audio band that is sent to the speaker to alert the user.
I think you misunderstood the design. The tone is intended to unmute
the speaker, so that the real call can be done by voice. That's why
the call tone needs to be ultrasonic.

Here is the schematic (my webserver is down at the moment, so I had to
use imageshack)
http://img253.imageshack.us/my.php?image=intercom1tb0.png

Some explanations:
The intercom is going to be used to link several flats spread over two
houses. Because people (especially some old women) live there, the
intercom needs to be as easy-to-use as possible, i.e. press button,
speak, release button, await answer.

You too can't expect these people wait for the line to become
inactive, so an interlock is included to avoid collisions on the
line.
That's why the line is raised to 2V while speaking, allowing simple
detection whether the line is in use or not.
Sometimes there will be need to call everyone, so every station will
react on a DC level on the line above 5V and unmute the speaker.
There is also support for an entry-phone. Because one can't expect
strangers to understand what a PTT is for, the PTT is moved into the
other stations.
The TAA4761 is a quad operational amplifier with high-current open-
collector output.


BTW: I'm from Germany so please be gentle with my English...


Ferdinand Meyer-Hermann
 
M

MooseFET

Jan 1, 1970
0
This could be a solution kicking a bunch of electronics out of the
device. But it requires some modifications. See below...> Now for a non-PIC based idea:


I'd prefer the sawtooth generated by the NE567, because it has a lower
harmonic content. But, if I find a source of these, I'll consider
them.
Note that this is a hobbyist's project, so I need to buy in small
quantities.

Try www.digikey.com They carry lots of linear stuff.

I think you misunderstood the design. The tone is intended to unmute
the speaker, so that the real call can be done by voice. That's why
the call tone needs to be ultrasonic.

Yes, perhaps I did. I had assumed that a person had to do something
at the receiving station.
Here is the schematic (my webserver is down at the moment, so I had
to

There is something wrong with the image. I can't see much of it.
There is a big square blank in the middle.
Some explanations:
The intercom is going to be used to link several flats spread over two
houses. Because people (especially some old women) live there, the
intercom needs to be as easy-to-use as possible, i.e. press button,
speak, release button, await answer.

Are they talking to a central station?

You too can't expect these people wait for the line to become
inactive, so an interlock is included to avoid collisions on the
line.
That's why the line is raised to 2V while speaking, allowing simple
detection whether the line is in use or not.
Sometimes there will be need to call everyone, so every station will
react on a DC level on the line above 5V and unmute the speaker.
There is also support for an entry-phone. Because one can't expect
strangers to understand what a PTT is for, the PTT is moved into the
other stations.
The TAA4761 is a quad operational amplifier with high-current open-
collector output.

BTW: I'm from Germany so please be gentle with my English...

Your english is quite good.


Perhaps more later. I've got to run.
 
M

Michael A. Terrell

Jan 1, 1970
0
This could be a solution kicking a bunch of electronics out of the
device. But it requires some modifications. See below...
I'd prefer the sawtooth generated by the NE567, because it has a lower
harmonic content. But, if I find a source of these, I'll consider
them.
Note that this is a hobbyist's project, so I need to buy in small
quantities.

I think you misunderstood the design. The tone is intended to unmute
the speaker, so that the real call can be done by voice. That's why
the call tone needs to be ultrasonic.

Here is the schematic (my webserver is down at the moment, so I had to
use imageshack)
http://img253.imageshack.us/my.php?image=intercom1tb0.png

Some explanations:
The intercom is going to be used to link several flats spread over two
houses. Because people (especially some old women) live there, the
intercom needs to be as easy-to-use as possible, i.e. press button,
speak, release button, await answer.

You too can't expect these people wait for the line to become
inactive, so an interlock is included to avoid collisions on the
line.
That's why the line is raised to 2V while speaking, allowing simple
detection whether the line is in use or not.
Sometimes there will be need to call everyone, so every station will
react on a DC level on the line above 5V and unmute the speaker.
There is also support for an entry-phone. Because one can't expect
strangers to understand what a PTT is for, the PTT is moved into the
other stations.
The TAA4761 is a quad operational amplifier with high-current open-
collector output.

BTW: I'm from Germany so please be gentle with my English...

Ferdinand Meyer-Hermann


http://www.national.com/mpf/LM/LMC567.html says that National has
discontinued the LM567 but still makes the low power version, the
LMC567. You should have no problem finding a vendor of National
Semiconductor in Germany.


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Are they talking to a central station?
No, there is no central station except a central 15-20V power supply.
All stations are wired in parallel. So there needs to be sort of an
algorithm to arbitrate who is will use the line next.

http://www.national.com/mpf/LM/LMC567.htmlsays that National has
discontinued the LM567 but still makes the low power version, the
LMC567. You should have no problem finding a vendor of National
Semiconductor in Germany.
I have no trouble getting the LM/NE/SE 567. The problem is the
LTC6906.

Ooops, I really don't know what has happened to the schematic, but
here is another try:
http://img518.imageshack.us/img518/5882/intercom1kb3.png


Happy Easter!
Ferdinand Meyer-Hermann
 
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