Microemission said:Thx for the response.
Didn't understand the last part fully.
The receiver states "Output Level L/R 0,5 Vss on 600 Ohm"
So what i need to do is to put the primary of a transformer with 600ohm on the output of the audio signal and then the secondary with 50 ohm (this is the impedance of twisted pair), and then on the receiver end a transformer with 50 ohm impedance on primary connected to the twisted pair and then the secondary with 150ohm (normal audio impedance i think) to feed the tv right ?
I found this nice page about transformer impedance matching too
h**p://farside.ph.utexas.edu/teaching/302l/lectures/node91.html
throwaway18 said:Interesting.
I have done speech and music over hundreds of meters of cat5 in buildings several times. I have not had a problem with high frequency loss. It sounds ok to me.
Last time I checked I can hear sounds up to about 15KHz. 10dB loss at 22KHz is not a problem.
Next time I will try a compensation capacitor.
I have found that screened cable gives fewer problem with picking up signals from other cables such as bleeping from fire alarm systems. Sometimes the screen needs to be conneced just at one end.
>but for telephone company and long distance is very importent parameters...
Telephones use bidirectional audio with hybrid circuit so impedance matching is more important. It helps that telephones only pass audio up to about 4KHz.
Microemission said:Very nicely explained xxargs!
Where can i get the Spice model of the Cat5 cable?
Or you did it yourself with the parameters u gave?
Microemission said:Just to confirm if I understood right, i should send L+Gnd over one twisted pair and R+GND over another both with a capacitor in parallel on the source of the signal, depending on what the distance is like you refered, correct?
No need for a capacitor on the receiver end as the one of the source is compensating for all the loss right ?
xxargs said:low educated Mr Pulpin invented if insert extra length inductance on line to compensate cable capacitanse (and blamed very much from scientific socity for this 'stupide idea' - you make a low pass filter!!!, and missing whole point) and decrace attenuate very much on low frequency, but cost more attenuate on high frequency depend of cable capacitance is a distrubed and inserted extra inductanse is discrete points.
in low frequence see very many of 'inserted inductance' in wavelength and accept as distrubed to give real impedances and no extra attenuate on little higher frequency
but high frequency see wery few 'inserted inductance' as dicrete points in wavelength and make daisy chain-coupled low pass filter. Pulpin balanced this to give very low and flat attenuate up to around 4000 Hz and frequecy above attenuate very quickly - enougt to make usable long distance phone call .
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