Research on calibration of demodulation loss of receiver

To solve the problem of the deviation of the demodulation threshold which is caused by quoting demodulation loss from the specification, a measuring method based on relationship between E
_b
/N
₀
and Bit error rate (BER) in theory is proposed. Utilizing the inverse-function of BER and the BER measured actually, the E
_b
/N
₀
in theory corresponding to the measured BER can be calculated. After multi times of measuring and calculating in different bit rate, a serial average data is obtained. And the difference of E
_b
/N
₀
between the transmitter and the average which is got from receiver is the demodulation loss, so a curve of demodulation loss versus bit rate can be build. 3 digital baseband equipment were tested, the demodulation loss is different from each other, and the maximum deviation is 1.4dB from the specification. The result proves that using the method discussed above is more accurate than quoting the specification and better for reflecting the individual characteristics.