This appnote can be downloaded from National's website, at:

http://www.national.com/an/AN/AN-402.pdf

HTH...

Dave

Vern Jones wrote...

>See if you can find a National Linear Applications Handbook--1986, look
>at AN-402. It discusses the LM1889 and LM2889 chips. The VSB Filter is a
>Vestigial Sideband Filter and is a pre-packaged circuit cut to channel 3
>and 4. You have the channel 3 and 4 Video Carriers (AM) and the channel
>3 & 4 Audio carriers (FM) 4.5 Mhz removed from the AM video carrier, and
>then the Chroma signal at 3.58 Mhz these frequencies are closely linked
>for a 6Mhz wide bandwidth for channel 3 or 4. The sound and Video
>oscillators use lc components, the SAW (VSG) filter is premanufactured
>you could probably design a LC band pass filter to limit the Vestigial
>side band. A TV channel has a lopsided picture bandwidth. It is 4.5 Mhz
>on the upper side band and 1.25 Mhz on the lower side band. The
>vestigial filter cuts off the lower 3 Mhz of the lower side band tho
>keep the video carrier from channel 3 from interfering with the audio
>and video carriers of channel 2.
>
>I dont have the document in pdf form or would send it, maybe someone
>else has it...

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