bipolar waveforms VS SUM waveforms

[walters]

bipolar waveforms

Bipolar waveforms - are not summed but are mixed with DC offset i guess

Dual waveforms- Are two seperate waveforms

AC waveforms- are alternating in polarity from positive to negative


In video electronics they use Bipolar waveforms


On the RED color channel they sum the RED color with the vertical sync, so when you look at the RED channel on the oscilloscope you will see a "bipolar waveform" it will be a red channel video waveform + the vertical sync riding ontop or DC offset to superimpose the vertical sync

They do the same with the BLUe color channel but they sum the hortizonal sync, so when you look at the Blue channel on the oscilloscope you will see a "bipolar waveform" its the blue channel video waveform + the hortizontal sync

Another Bipolar waveform example is

The sum/bipolar the RED color channel with the LEFT audio channel and the BLUE channel they sum/bipolar RIGHT audio channel

Bipolar waveforms VS summing waveforms are difference because Summing would take 2 different waveforms and merge them together into One.

Bipolar waveforms examples:
1.) analog video signal + digital vertical or horizontal sync waveforms on ONE channel or single ended channel
2.) Analog Video signals + audio left or right channels onto a single ended channel or ONE channel

THey use differential Op-amps in differential MODE to Input pin#1 will be the analog video signal RED and Input pin#2 will be the vertical sync signal

They use these Video driver op-amp chips that do this so you can mix video signals with digital vertical and horizontal sync signals

**DOn't ever SUMM or Bipolar audio with Digital signals this will create buzzing and noises**

Why is it a "bipolar" waveform and not a summed waveform#1::
is because on the oscilloscope display on ONE channel you can see 2 difference waveforms, you can see the RED channel + the vertical sync seperated by DC offset it seems, even when the oscillscope is on the AC coupled the bipolar signals are still riding/superimposed or seperated from one another

Why is it a "Bipolar" waveform and not a summed waveform#2::
is because the op-amp is in differential mode using the input pin positive (+) and input pin negative (-)

Bipolar waveform#1 example:
Video RED channel is on input pin (+)
Vertical sync is on input pin ( - )
Output is Bipolar = Video red channel with the Vertical sync

Bipolar waveform#2 example:
Video RED channel is on input pin ( + )
Audio LEFT channel is on input pin ( - )
Output is Bipolar = Video Red channel with the Audio Left channel

Bipolar waveform#3 example:
Video BLUE channel is on input pin ( + )
*Digital logic* , clocks signals , data lines , control lines on input pin (-)
Output is Bipolar= Video Blue channel with digital signals etc.

Summing would need summing resistors and its a single ended input and single ended output

I think with summing you can't SUM or mix analog signals with digital signals

I'm not sure with summing you can sum/mix video signals with digital signals

 

[walters]

how to sum of waveform

unipolar signal
1.) A rectified waveform
2.) a digital signal staying at ground to positive or ground to negative

bipolar
1.) AC alternating polarities or AC component + Digital DC component or DC toggling levels


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Bipolar MIXING and summing lesson:

74HC74 chip ( its a flip flop )
1.) D input
Clock input
Q output

Bipolar mixing stage/chip:
2.) Put the Audio waveform in the D input
3.) Put the Digital waveform signal in the Clock input

Bipolar output stage/chip:
4.) Q output of the 74HC74 is going to have Audio signal + the Digital signal how so ??



EL5370 video chip:

Bipolar mixing stage:
1.) Red,green,blue colour " analog" inputs goes to the EL5370 video chip inputs
2.) 74HCT86 Vertical sync and horizontal sync "digital" signal goes to the EL5370 video chip inputs

Bipolar output stage:
3.) EL5370 video chip outputs Bipolar waveforms
a.) RED channel is analog + vertical sync is digital signal
b.) BLUE channel is analog + horizontal sync is digital signal

4.) On the oscilloscope viewing the RED channel you will see a "bipolar waveform" because you will see the RED channel that is analog AC and the vertical sync which is a digital signal, you see a AC component and a DC component at the same time on the single ended channel #1 on the oscilloscope this is a True bipolar signal