help me for this circuit

[klick]

Hi,
I have a problem with this circuit:
AUDIO-IN is a sine wave that goes from 300Hz to 4KHz.
the sigals OUT1 and OUT2 should be 180 degrees out of phase.
but they are out of phase about of 110 degrees.
I don't understand why.....

This is a problem for my application.

someone could help me????

thanks

 

[Prototyp_V1.0]

I guess you by "out of phase" mean you compares out1 and out2 against each other.

It's fully understandable that you don't get exactly 180 deg phase difference, because any voltage drop (AC) over L1 will cause phase difference to occur.

 

[klick]

Yes,I compare OUT1 and OUT2.

But, how I do get a difference of 180, also by changing the circuit??
I can't remove L1 and L2

tanks

 

[keith1200rs]

I think your problem is the transformer, not L1/L2. What is the inductance and turns ratio of T1?

Keith.

 

[yangjinhua]

the small signal circuit . the out-1 is connect the L1 and L2 to the ground

Added after 6 minutes:

the small signal circuit . the out-1 is connect the L1 and L2 to the ground

 

[klick]

this is part of a more complex circuit
instead of the trasformerr could be a capacitor and the phase is the same
ground on the right is the mass of the entire circuit

 

[keith1200rs]

Without more details it is impossible to say what the problem is. The BD139 emitter follower will not cause a large phase shift at 300Hz - 4kHz. With the 10uF coupling capacitor the phase will start to shift maybe 10 degrees at 30Hz and increasing as the frequency decreases. The problem is with what you aren't telling us - the load? T1 inductance?

Keith.

 

[klick]

I enclose the full scheme

In BUS1 and BUS2 there are audio and power (28V)

BLOCK1 and BLOCK2 talk and listen and vice versa

When send the audio signal from AUDIO-IN of BLOCK-1, at the out AUDIO-OUT of the same block there should be no signal, because IC1 sum signal and cancel them if the emitter and collector of Q2 are 180 degree out of phase THAT IS THE PROBLEM......
The audio signal flows through D1 and through the BUS comes in AUDIO-OUT of BLOCK-2

thanks

 

[keith1200rs]

OK, that is different to your earlier circuit and a lot easier to see the problem. I assume you are trying to send audio over the 28VDC lines. You seem to want to prevent the transmitted audio from being received at the transmitted audio end. The problem with the way you are trying to do it is that for Q2 to produce complementary ouptuts on its emitter/collector it needs to see the same load at the emitter and collector. Your loads are totally different. That will give both a gain and phase error.

Keith.

 

[Prototyp_V1.0]

Yes,I compare OUT1 and OUT2.

Then L1 and L2 is the components that cause phase difference differs from 180 degrees.

But, how I do get a difference of 180, also by changing the circuit??
I can't remove L1 and L2

If your requirement is to put through sinus shaped signals with varying frequenzy, that I think isn't possible to achieve.
However, if freq is fixed, you can try to put a cap over L1 and L2 that do have the same reactance as L1 and L2 (just with oposite polarity).
However, that may work or it may not work - but you can always give it a try. The consequence should be that a bigger part of signal voltage would now stay over L1||C1 and L2||C2.

 

[klick]

The range of frequency is about 300Hz- 4KHz
whit L1 and L2 the BLOCK1 and BLOCK2 see high impedance to DC generator, if I put a capacitor in parallel their, the impedance in audio band decrease.
L1 and L2 should be greater for to see more high impedance

 

[FvM]

The circuit is basically driving the "bus" single ended, because the negative line is clamped to the circuit ground. So I wonder where you expect differential signals, that are 180° out of phase.

At the driver side, Q2 emitter and collector voltage can be expected out of phase, but this property doesn't matter for the circuit operation, I think.

Referring to the said 110° phase difference. You didn't tell, how you measured it and for which frequency it is achieved.