Here is AN-402 http://www.analog.com/library/applicationNotes/amplifiersLinear/highSpeed/AN-402.pdf The AN says that the LM2889 is very similar. Identical RF function and pin outs, so here is the datasheet for LM2889. http://www.cedmagic.com/tech-info/data/lm2889.pdf - end --- 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... > >Vern Jones > >Herbert Graf wrote: >> >> Was wondering if anybody one the list could help me with this one. I >> recently purchased an RF modulator from www.bgmicro.com to convert composite >> video to ch2 which uses the LM1889. I am having trouble in two ares. >> >> First the data I have says that I have to feed in a "chroma carrier", what >> the heck is that? Is that just a 3.79... MHz signal? Any idea on what kind >> of amplitude would do? >> >> Second the module only has ch3 and ch4 as choices, I would like to convert >> it to ch2 operation, I think I know how to modify the oscillator section but >> there is a section in the module labeled "ch3 VSB", I assum this is tuned >> for the Ch3 frequency and that I would have to change this circuitry as well >> to get it to work? >> >> Basically I'm looking for anyone who's worked with this chip, and anybody >> who has a datasheet (national no longer has the datasheet). Thanks for any >> assistance. TTYL _____________________________________________________________ Get your free email here at http://www.e-ha.com -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads