Reducing spurious PLL tones in spectrum sensing architectures

In a non-ideal PLL circuit, leakage of the reference signal into the control line produces spurious tones. When the distorted PLL signal is used in an analog-to-digital converter (ADC), it creates spurious tones in the sampled data as well. In spectrum sensing applications, the presence of spurious tones can lead to false detection of signals in otherwise empty channels. In a typical spectrum sensing application, there usually exists a Fourier transform block. We propose an algorithm to use this block to estimate the jitter errors from the spurious sidebands and to compensate the distorted samples in the digital domain. Index Terms-PLL, sideband suppression, spurious tones.