The economic activity indicators in Poland during the years 1995‒2011 exhibit various cyclical patterns. Employing the Christiano – Fitzgerald band-pass filter and unobserved components model it is shown that the cyclical processes of Polish economic activity are driven by overlapping higher frequency fluctuations (3‒4 years) and longer cycles of 8.5 years. The cyclical fluctuations of construction, transportation and trade are dissimilar to gross value added. Economic activity in transportation leads and in construction lags the fluctuations of gross value added. Cyclical fluctuations of gross value added seem to be determined by industry and construction. Manufacturing, especially capital and intermediate goods fluctuations are responsible for the variation of industry. The production of non-durable consumer goods, energy and production of electric power are relatively the most desynchronized compared to industry. Production of electric power leads industrial production. Capital goods, intermediate goods and energy cycle phases are asymmetric – the slowdown lasts shorter and has higher amplitude compared to expansion. During the last crisis occurred the intensified variation of economic activity in Poland.

This paper presents the design and measurements of low-noise multichannel front-end electronics for recording extra-cellular neuronal signals using microelectrode arrays. The integrated circuit contains 64 readout channels and is fabricated in CMOS 180 nm technology. A single readout channel is built of an AC coupling circuit at the input, a low-noise preamplifier, a band-pass filter and a second amplifier. In order to reduce the number of output lines, the 64 analog signals from readout channels are multiplexed to a single output by an analog multiplexer. The chip is optimized for low noise and good matching performance and has the possibility of pass-band tuning. The low cut-off frequency can be tuned in the 1 Hz - 60 Hz range while the high cut-off frequency can be tuned in the 3.5 kHz - 15 kHz range. For the nominal gain setting at 44 dB and power dissipation per single channel of 220 μW, the equivalent input noise is in the range from 6 μV - 11 μV rms depending on the band-pass filter settings. The chip has good uniformity concerning the spread of its electrical parameters from channel to channel. The spread of the gain calculated as standard deviation to mean value is about 4.4% and the spread of the low cut-off frequency set at 1.6 Hz is only 0.07 Hz. The chip occupies 5×2.3 mm2 of silicon area. To our knowledge, our solution is the first reported multichannel recording system which allows to set in each recording channel the low cut-off frequency within a single Hz with a small spread of this parameter from channel to channel. The first recordings of action potentials from the thalamus of the rat under urethane anesthesia are presented.

This paper presents a broadband Switch-Mode Power Amplifier (SMPA) using a Band-Pass Filter (BPF) at the Output Matching Network (OMN). The proposed SMPA integrates a microstrip BPF as an output impedance matching network to significantly reduce the final circuit size. The microstrip lines of the filter simultaneously play the role of filtering and impedance matching. This proposed method reduces the size of the PA and reduces the power dissipation as much as possible. The BPF is placed at the output of the circuit using microstrip lines and the RT Duroid 6006 substrate. This BPF covers a wide bandwidth ranging from 3.0 GHz to 4.4 GHz. Simulation results show 9-14 dB gain with 44 - 56.6 % drain efficiency ( DE %), and the output power of 39 – 41.3 dBm would be achieved across the frequency band from 3.0 GHz to 4.4 GHz.