Ensemble Designs 7160 Serial Digital Protection DA - Manual (Page 6)

www.ensembledesigns.com 7160-6
Model 7160 HD/SD/ASI/310 Protection DA
The Pri ASI Status indicator show what has been detected in the incoming DVB-ASI or SMPTE 310M
stream.
Possible indications are:
Good • – The DVB-ASI or SMPTE 310M signal passes all tests (either Simple or Advanced)
No ASI • – No DVB-ASI or SMPTE 310M signal has been detected
No Packets • - All of the packets in the stream are null. There are no actual program packets
No PAT • - There are non-null packets, but no Program Allocation Table can be found
No PMT • - No Program Management Table can be found
No Video • - The user-defined minimum number of video packets per second has not been met
No Audio • - The user-defined minimum number of audio packets per second has not been met
The ASI Status menu shows a breakdown of these elements of analysis with a display of live results.
The displayed values for the rate (in PIDs per second) for the video and audio can be used as a guide to
setting the Min Vid Rate and Min Aud Rate values for a particular system or installation.
Whenever the DVB-ASI test generates a result other than Good, a timer begins running. If that timer
reaches the ASI Time value set in the ASI Config menu, the channel will be marked as faulted and the
switch will move to the Secondary input.
When the program assignments in a DVB-ASI stream change, it can take up to a second for the 7160
detector to re-acquire all of the table information needed to show that the signal is good. For this
reason, a setting of between 2 - 5 seconds is recommended for the ASI Time parameter.
The Pri Errors menu shows error-seconds counters for all tests performed by the 7160. The ASI Vid
ErrSec control shows the cumulative number of seconds where the minimum packet rate was not
met. Depending on how the ASI Time control is set, these errors may or may not have actually caused
a program switch to occur. To reset the error-seconds counters, click them.
Block Diagram
The block diagram on the following page illustrates the signal flow of the 7160. Note that in the event
of power failure, the passive relay passes the primary input to the Relay Protected Output.
The Primary and Secondary inputs pass through serial digital receiver/equalizers for buffering. When
a fault is detected in the Primary input, and the Secondary input is seen as not faulted, the electronic
solid state switch will activate, switching the Secondary input to the output.