
Interface Configuration and Interpretation
Constellation Provides the option to set the modulation scheme:
Select the required value from the
Inversion The sense of modulation may be inverted due to the number of mixing stages in the installation. Enabling the Inversion checkbox will allow the demodulator to lock onto a received signal with an inverted spectrum.
PLL Bandwidth This control modifies the bandwidth of the carrier phase recovery loop, which is responsible for
AFC Range | Two carrier recovery ranges are available: Normal and Wide. In |
| Normal mode, the range is approximately ±150 kHz. In Wide |
| mode, the range is increased to ±500 kHz. Normal setting is the |
| default setting and is recommended for most applications. |
Analysis Mode | Two settings are available: MPEG mode and QAM mode. In |
| MPEG mode, the lock condition is declared as “No Lock” if a |
| valid transport stream cannot be detected. This prevents spurious |
| streams from being fed to the MPEG processor for analysis. In |
| QAM mode, the validity of the MPEG stream is ignored, |
| possibly resulting in spurious MPEG analysis, but allowing lock |
| to be asserted if the QAM receiver front end sees a valid QAM |
| signal. This allows the display of RF data and constellations |
| even if the MPEG data is not valid. In QAM mode, the |
| MTM400 behaves more like a conventional QAM analyzer. |
| MPEG mode is the default setting and is recommended for most |
| applications. The range controls, PLL bandwidth and AFC |
| range, are operable in both MPEG and QAM analysis modes. |
BER | Bit Error Rate (pre Reed Solomon). |
MTM400 MPEG Transport Stream Monitor User Manual |