What is carrier imbalance and how can I correct it?

imbalance
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What is carrier imbalance and how can I correct it?

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In an ideal world, the carrier of an m-sequence modulated PSK signal would be suppressed to a level below that of the main lobe. Specifically, it would be suppressed by 10 log(N) dB, where N is the period of (number of chips in) the PN sequence. (If the sequence isn’t an m-sequence, carrier suppression isn’t guaranteed.) In the real world, however, ideal suppression doesn’t occur for a number of reasons. For example, there will always be a certain amount of carrier feed-through in a real mixer. Regardless of the cause, degradation of carrier suppression is referred to as carrier imbalance. If sufficiently degraded, the carrier level may actually exceed that of the main spectral lobe. It is interesting to note that a small degree of carrier imbalance may add destructively with the natural carrier component, thus actually improving carrier suppression. Nevertheless, this is still considered a carrier imbalance. Any unnatural DC bias in a PN sequence will contribute to carrier imbalance.

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