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That's a good idea, converting an old FM-MPX decoder to operate with MTS tv audio, BUT, remember that MTS audio's L-R component is compressed with dbx noise reduction and must be re-expanded to sound right. Many cheap tv sets and vcr's use a cheaper circuit to achieve the required expansion, but they do re-expand the dynamic range of the L-R component before it reaches the matrix that reconstructs the L and R signals from the L+R and L-R components. The MTS pilot tone is 15.734kHz (same as the horizontal sweep rate), by the way. Did you know that b/w sets originally used 15.750 kHz as the horizontal sweep frequency and 60Hz as the vertical? When color sets were introduced, the sweep rates were slightly altered to 15.734kHz and 59.97Hz respectively to eliminate some pesky interference that was a byproduct of the chroma channel.
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