Error injection using PC based modulator

[kirubanithi]

Injecting error in the transport stream using the pc based modulator whether will affect the BER of the stream. Because while my testing the BER is not even varying but Transport stream error packet count will increase. Any one could you please the above beghaviour.

 

[poor mystic]

Hi Kirubanithi
It is a long time since my training and not only have I forgotten much but much has changed. Also I admit to some guesswork in what follows.

It sounds to me as though you are sending yourself some data, messing with the data stream, and watching the error rate at the receive end of the bearer.
I believe any packets which are found to be corrupted at receive will be resent under command of the application which wants the data.
The numbered packet will possibly have gone missing when it is blocked at X25 level (packet data protocol) by the X25 modems in the local concentrator, whose functions must always include a test of the crc (cyclic redundancy check) which is sent as part of the packet.

After all nobody is interested in corrupt data, and data corrupted (due to faulty cable for instance) can be prevented from uselessly loading a network by careful testing to see that only actual data is sent.

(sorry no snappy signature yet)

Anyway, that's what I think I would have said 20 years ago.

 

[kirubanithi]

As per the above explanation is there any possibilities to increase in BER of the stream. Or if there is no increment in BER of the stream means could you please explain the cause.

 

[poor mystic]

Hi again Kirubanithi
If my notion above is correct, I would elaborate by mentioning that more than one means of measuring 'bit error rate' exists.
In the opinion of a high-level application sending pseudo-random code over a noisy packet link, the link will be slower but still noise-free up to some limit. This is an artifact of the protocol, and in fact is the whole reason for the packet protocol's existence.
So the error-detection/correction in a shell of the communications system beyond ken of your BER software may be responsible for the intriguing effect.
It's a suggestion, no more.

 

[DeeNos]

I would like to address the issue of error injection using a PC-based modulator and its potential impact on the BER of the transport stream.

Firstly, it is important to understand that the BER (bit error rate) is a measure of the number of bit errors that occur in a given period of time in a communication system. This can be affected by various factors such as noise, interference, and channel conditions.

In the case of injecting errors using a PC-based modulator, it is possible for the BER to be affected. This is because the modulator is responsible for encoding the data into a format that can be transmitted through the channel. If errors are introduced during this process, it can lead to a higher BER.

However, it is also important to note that the BER may not always be a reliable measure of error introduction in the transport stream. This is because the transport stream may have error correction mechanisms in place that can correct errors and maintain a low BER even when errors are introduced.

In this scenario, it is possible for the transport stream error packet count to increase while the BER remains relatively unchanged. This could be due to the error correction mechanisms compensating for the errors introduced by the PC-based modulator.

To fully understand the behavior observed during testing, it would be necessary to analyze the specific error correction mechanisms in place and their effectiveness in correcting errors introduced by the modulator.

In conclusion, while the use of a PC-based modulator for error injection can potentially affect the BER of the transport stream, it is important to consider other factors such as error correction mechanisms and their impact on the overall error rate. Further analysis and testing may be needed to fully understand the observed behavior.