Which measure indicates the quality of signal being transmitted?

The measure that indicates the quality of the signal being transmitted is the Bit Error Rate (BER). BER is a critical parameter that measures the number of bit errors that occur in a transmitted data stream after it has been subjected to noise and other factors that can affect signal integrity. It is expressed as a ratio of the number of erroneous bits to the total number of transmitted bits within a specific time frame.

A lower BER indicates a higher quality of the signal, translating to fewer errors and more reliable communication. Therefore, this metric is important for evaluating the performance of communication systems and ensuring that data is transmitted accurately.

Signal Strength, while important, primarily assesses the power level of the signal rather than its quality. Modulation Error Ratio is another measure of performance but it is more focused on the specific modulation scheme's distortion rather than a general quality metric. Downstream Bandwidth pertains to the capacity of the channel and does not directly measure signal quality. Therefore, Bit Error Rate is the most appropriate measure for indicating the quality of the signal being transmitted.