B - 1 0

D i a g n o s t i c s

 

 

PCR Lock OSD Only

The PCR lock indicates a program-clock-reference lock with the current digital datastream.

Signal - To - Noise Ratio (SNR) and Automatic Gain Control (AG ￿ C)OSD Only

The SNR displayed on the OSD is a rough estimate of the carrier signal-to-noise ratio. The SNR displayed is a measure of the QAM cluster variance, which is proportional to the signal-to-noise ratio.

The AGC value roughly indicates the received signal level.

Analog channels display analog for carrier lock. The SNR and AGC display a number for the numeric value and blank for the ssss value. A blank display indicates that the digital section of the DCT 2000 is still in the initial state. If this occurs, check diagnostic d07.

Table B-9 lists the SNR and AGC indicators for the OSD:

Table B - 9

SNR and AGC indicators OSD only

s s s s value

Meaning

GOOD

Good value

FAIR

Marginal signal level check the signal

BAD

Unusable signal

d 04: In Band Error

The error count represents the number of uncorrectable errors in the digital multiplex. The QAM receiver must be locked to the signal before errors can be detected. A four-digit value of 0000 displayed on the LED indicates that there are no uncorrectable errors. The display shows the short-term error count and is updated every five seconds. The maximum count is 9999.

The long-term error count is a sum of the errors occurring over the last 24 hours of DCT 2000 operation. This data is maintained between channel changes and power cycles. This count is reset every 24 hours of DCT 2000 operation. The maximum is 9999 counts.

Figure B-8 shows the receiver status error count on the LEDs:

Figure B - 8

In - band receiver status error count short term LEDs

When there is no carrier lock, the LEDs display four dashes (−−−−).

DCT 2000 Installation Manual

Page 52
Image 52
Motorola DCT 2000 installation manual Band Error, PCR Lock − OSD Only, S s value Meaning