Service manual

STP 11-25R13-SM-TG
3 - 43
Performance Steps
Table 3-1. MTS Baseband Transmission Performance Objectives
Table 3-2. MTS Baseband Transmission Crosstalk Objectives
NOTE: The stereo audio is an amplitude-modulated, double sideband, suppressed-carrier (DSSC) signal
that applies to both the stereo and the SAP channels.
(2) The control of incidental carrier phase modulation (ICPM) of the visual carrier is the single
most important performance characteristic controlling the quality of the MTS. To measure
ICPM requires a demodulator having both envelope and quadrature detectors and a WFM.
(3) Excessive ICPM creates sync buzz in receivers, mainly in the stereo channel but to a
lessor extent; also in the main channel. Limit ICPM to 3 degrees for luminance and to 5
degrees during sync, which equates to a sync buzz level of 40 dB and -36 dB,
respectively, referenced to 25 kHz deviation.
3. Localize the trouble to a specific circuit by analyzing overall block diagrams and by performing
functional tests on suspected circuits.