Vesa Lehtinen

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In order to obtain a higher spectral separation from the BPSK-like signals, i.e. GPS C/A code, the signals proposed for future Galileo and GPS M-code signals are processed using split-spectrum type modulations, such as Binary Offset Carrier (BOC) modulation. These BOC modulations create deep fades (ambiguities) in the envelope of the Autocorrelation(More)
Carrier aggregation transmissions in frequency division duplexing devices reduce the duplexing distance between the transmitter (TX) and receiver (RX) bands. As a consequence, the spurious intermodulation distortion products created by the nonlinear RF front-end of the TX may easily extend over to the RX band, potentially causing own RX desensitization. In(More)
This article addresses some implementation challenges in the potentially very energy-efficient charge-sampling radios. Alternative ways to implement charge sampler in charge sampling radio are considered, and the impacts and spectral shape characteristics of the sampling jitter induced signal distortion are analytically studied in these cases. The analysis(More)
In frequency division duplex transceivers employing non-contiguous carrier aggregation (CA) transmission, achieving sufficient isolation between transmit and receive chains using radio frequency filtering alone is increasingly difficult. Particularly challenging problem in this context is spurious intermodulation (IM) components due to nonlinear power(More)
The variable fractional-delay (FD) filter structure by Tassart and Depalle performs Lagrange interpolation in an efficient way. We point out that this structure directly corresponds to Newton's interpolation (backward difference) formula, hence we prefer to refer to it as the Newton FD filter. This structure does not function correctly when the fractional(More)
The cascaded integrator-comb (CIC) filter is an efficient multiplier- free structure for decimation and interpolation. However, due to its narrow stopband notches, it is useful only when the signal of interest has a small bandwidth compared to the input and output sample rates. Consequently, it can only be used in the first (last) few stages of multistage(More)