How to detect 2 MBPS connection
- Thread starter santhoshR
- Start date
Presence and failure???
Do you mean just detecting signal present/not present...?
64Kbps needs to be monitored...
Again, just detecting signal present/not present...?
Or actually checking for some kind of validty?
What is your electronics skill level and , oh, where does the PICAXE come into this ?
This is a PICAXE (and related electronics) Forum.
For specific electronics on specific Comms you should find an appropriate Forum.
Do you mean just detecting signal present/not present...?
64Kbps needs to be monitored...
Again, just detecting signal present/not present...?
Or actually checking for some kind of validty?
What is your electronics skill level and , oh, where does the PICAXE come into this ?
This is a PICAXE (and related electronics) Forum.
For specific electronics on specific Comms you should find an appropriate Forum.
Sorry ... I dont know any good electronic forum website.. so I have posted my query here .. Please help me to detect signal present/ not present ..... This is not actually for me, Its for my friend who has more than 30 years of experience in electronics and communication fields, He wants to develop an alarm device which raises an alarm if there is an absence of 2MBPS signal and also for 64KBPS ... Please help ...
Thank You
Thank You
What level are these signals (TTL, other)?
Can the signals be connected to directly or only indirectly (induction, etc)?
Are they continuous or periodic?
What power is available for the monitoring circuitry (5 volts, 3 volts)?
What type of alert is needed on signal failure?
With "30 years of experience" I would think your friend has the knowledge for a direct-connect monitor: a wide-band CMOS op-amp and a rectifier to create a DC signal proprotional to the signal level, with a capictor sized for the proper delay.
John
Can the signals be connected to directly or only indirectly (induction, etc)?
Are they continuous or periodic?
What power is available for the monitoring circuitry (5 volts, 3 volts)?
What type of alert is needed on signal failure?
With "30 years of experience" I would think your friend has the knowledge for a direct-connect monitor: a wide-band CMOS op-amp and a rectifier to create a DC signal proprotional to the signal level, with a capictor sized for the proper delay.
John
hippy
Ex-Staff (retired)
If a 0V/+V signal, always 0V when not present, a diode fed RC circuit should do the job; charging near instantly when signal present, discharging slowly when not, it will hit a low level some time after the signal is no longer present. It may need some buffering and/or interfacing either side of the RC but that's the model I'd use. One could use an actual RC or perhaps replace it with a PICAXE.
"Shirly there is a heap of differance between a 'signal' being present on a line and it being valid ?"
- Umm, srnet, that's why I asked my question in post 2 and santhoshR replied "to detect signal present/ not present..." in post 3. Yes/no?
And stop calling me Shirley.
I'd go along with Papa's suggestion ... which solves hippy's "may need some buffering ".
I would think 100% it would need "buffering" as any significant degradation of the original signal would upset the comms.
Just tapping off with an RC could be asking for trouble as it could upset all sorts of things.
I would experiment with a high impedance buffer op-amp + rectifier as suggested by Papa.
And don't just hack around with cables otherwise you could upset impedances.
Surely (Shirly) a man with 30 years electronics experience could suss this?
Then, of course, we put the signal into a PICAXE ADCin and write some code.
And you may need a nice Tektronix scope to optimise this.
- Umm, srnet, that's why I asked my question in post 2 and santhoshR replied "to detect signal present/ not present..." in post 3. Yes/no?
And stop calling me Shirley.
I'd go along with Papa's suggestion ... which solves hippy's "may need some buffering ".
I would think 100% it would need "buffering" as any significant degradation of the original signal would upset the comms.
Just tapping off with an RC could be asking for trouble as it could upset all sorts of things.
I would experiment with a high impedance buffer op-amp + rectifier as suggested by Papa.
And don't just hack around with cables otherwise you could upset impedances.
Surely (Shirly) a man with 30 years electronics experience could suss this?
Then, of course, we put the signal into a PICAXE ADCin and write some code.
And you may need a nice Tektronix scope to optimise this.
Read up on op-amps.
Signal line ---- Op-amp --- rectifier ----> PICAXE ADC.
The Op-amp provides a high-impedance buffer so (theoretically) it won't affect the original data traffic signal. The signal coming out of the Op-Amp now has enough oomph to go to a basic rectifier or RC circuit.
The capacitor will therefore charge partially when a digital on/off signal is applied.
Therefore there will be a verying voltage across the capacitor which roughly reflects the original data traffic.
Feed this into PICAXE . ReadADC in code. You will get a number that roughly reflects data traffic. Job done.
All your connections etc. will have to be perfect so you don't distort the original data signal.
It may be that with multiple / averaging ADC sampling you could get away without a rectifier.
But that's 'play time' i.e. experimental stuff for you to do.
Signal line ---- Op-amp --- rectifier ----> PICAXE ADC.
The Op-amp provides a high-impedance buffer so (theoretically) it won't affect the original data traffic signal. The signal coming out of the Op-Amp now has enough oomph to go to a basic rectifier or RC circuit.
The capacitor will therefore charge partially when a digital on/off signal is applied.
Therefore there will be a verying voltage across the capacitor which roughly reflects the original data traffic.
Feed this into PICAXE . ReadADC in code. You will get a number that roughly reflects data traffic. Job done.
All your connections etc. will have to be perfect so you don't distort the original data signal.
It may be that with multiple / averaging ADC sampling you could get away without a rectifier.
But that's 'play time' i.e. experimental stuff for you to do.