Eb/No literally translates to a ratio of bit energy to noise power in a 1 Hz bandwidth. This is a useful expression for expressing signal to noise ratio (SNR). BER is simply the bit error rate of digital transmission. The lower the Eb/No, the higher the BER. Every digital radio uses a modulation scheme that will have an ideal Eb/No vs. BER curve. In order to benchmark the actual hardware to the theoretical, a noise signal is summed with the data modulated test signal setting up a laboratory calibrated Eb/No which is then fed into a bit error rate tester (BERT) to determine the systems actual curve. (Figure 2)
Traditionally 70 MHz and 140 MHz satellite modems were tested using the now defunct HP3708A noise and interference test set. New C/N generator models such as the CNG70/140 from Micronetics have improved upon the measurement capability to provide accurate Eb/No setting even for 7/8 coding, turbo coding and 256 QAM modulations. In addition, extended L-Band Eb/No test sets are now available. In addition microwave noise generators are also available for full link testing RF to RF.
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Link to Carrier to Noise Generator product brochure |