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THS7372: input NTSC signal to a FHD channel

TAKASHI SUMI
Prodigy 20 points
Part Number: THS7372

Hello, 

I want to input NTSC signal to a FHD channel to get better horizontal resolution (even if only slightly).

Are there any problems?

Thank you

  • 0
    TI__Genius 11040 points

    Hello,

    There should be no concern from a device standpoint to inject the signal into the FHD channel, however there is a chance of aliasing to occur as the FHD channel has a much wider LPF range at 72MHz instead of the optimal 9.5MHz filter on the SD channel for NTSC signals.  This channel was not designed for this type of signal; however, we do have an EVM on the product's homepage to test this configuration. The section called "Low-Pass Filter" in the datasheet sheds more light on the reasons for the implemented filters in the device as this would be the major concern with injecting the signal to the FHD channel.

    Best Regards,

    Ignacio

  • 0 in reply to Ignacio Vazquez Lam1
    Prodigy 20 points

    Hello, Ignacio

    Is there a chance of  aliasing to occur even if I input the low-pass filtered signal to THS7372?

    (Does the aliasing occur by amplifying the signal in THS7372?)

  • +1 in reply to TAKASHI SUMI
    TI__Genius 11040 points

    Hello Takashi-san,

    Aliasing is an unwanted by-product of a sampled data system such as a DAC. The internal low-pass filter of the THS7372 minimizes the potential for aliasing as the signal goes into the next stage such as an ADC by effectively removing unwanted frequency components that would alias back into frequency band we are interested in. The THS7372 wouldn't cause any aliasing directly. 

    Best Regards,

    Ignacio

  • 0 in reply to Ignacio Vazquez Lam1
    Prodigy 20 points

    Hello, Ignacio-san

    Thank you for the reply.

    I understand.