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(ADA4433-1) To connect ADA4433-1 to ADI Video decodor

Hi !

I have some questions about ADA4433-1.

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Q1)

Our customer are planing to make evaluation board to change "single-CVBS" to "Diff-CVBS" to input ADV7281A-M.

To connect to ADI video decoder,  I think AC-coupling is necessary.

At ADA4433-1 datasheet page.22 Figure 55, there is "Difference Amplifier in a DC-Coupled Configuration" reference circuit.

Do you have "Difference Amplifier in a AC-Coupled Configuration" reference circuit?

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Q2)

Our customer will use like this.

"CVBS source" => "Single-CVBS" => "ADA4433-1" => "Diff-CVBS" => "ADV7281A-M"

Do our customer have to do AC-Coupling between "CVBS source" and "ADA4433-1"?

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Q3)

Do our customer have to do AC-Coupling between "ADA4433-1 source" and "ADV7281A-M"?

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Q4)

At ADA4433-1 datasheet Page.15, this is written.

Does this mean whether AC-coupled or DC-coupled, we do not change the connection of -IN and we need to bias with half the amplitude of + IN?

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Q5)

At ADA4433-1 datasheet Page.15, this is written.

Our customer are planing to use these value for each components.

C1 = 22uF

R1 = 62kOhm

R2 = 27kOhm (1V bias

*Fc = 0.26Hz.

How should they decide these value for each components?

Do you think that there is no problem with these values?

How should the cutoff frequency of the high-pass filter be taken into consideration while considering the NTSC signal frequency? (Does sag do not occur?)
Since 1Vpp signal is supposed to be input, is it OK to understand that 1.0 V bias is OK?
When deciding each constant, is there a point to consider other than the cutoff frequency and the bias voltage?

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Best ragards

Kawa

Parents
  • Hi Goz

    Thank you for your reply.

    I understood.

    I will wait your additional answer.

    Actually, if your CVBS source is what have you said is 1Vpp, and do not vary AC coupling is not necessary. You can just put a dc bias circuit the same on the Figure 53 on the datasheet.

    Do you mean that our customer don't need to do AC coupling between CVBS source and ADA4433-1 if GND is same?

    What will happen if CVBS source output is 1Vpp but 0V bias?

    Also please give me some advice for these question too.

    How should the cutoff frequency of the high-pass filter be taken into consideration while considering the NTSC signal frequency? (Does sag do not occur?)
    Since 1Vpp signal is supposed to be input, is it OK to understand that 1.0 V bias is OK?
    When deciding each constant, is there a point to consider other than the cutoff frequency and the bias voltage?

    Best regards

    Kawa

Reply
  • Hi Goz

    Thank you for your reply.

    I understood.

    I will wait your additional answer.

    Actually, if your CVBS source is what have you said is 1Vpp, and do not vary AC coupling is not necessary. You can just put a dc bias circuit the same on the Figure 53 on the datasheet.

    Do you mean that our customer don't need to do AC coupling between CVBS source and ADA4433-1 if GND is same?

    What will happen if CVBS source output is 1Vpp but 0V bias?

    Also please give me some advice for these question too.

    How should the cutoff frequency of the high-pass filter be taken into consideration while considering the NTSC signal frequency? (Does sag do not occur?)
    Since 1Vpp signal is supposed to be input, is it OK to understand that 1.0 V bias is OK?
    When deciding each constant, is there a point to consider other than the cutoff frequency and the bias voltage?

    Best regards

    Kawa

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