It is known that multiple trellis coded PSK (MTC-PSK) can achieve larger performance gain, and trellis coded continuous phase modulation (CPM) combined with Multi-h scheme can also achieve good power bandwidth tradeoffs. In this paper, we propose multiple trellis coded CPFSK (MTC-CPFSK), combined with Multi-h scheme to achieve further coding gain over MTC-PSK. We find that MTC-CPFSK with Multi-h scheme achieves lager squared minimum Euclidean distance and diminishes the number of merge events up to 10Ts depth in the state trellis. We also find that the number of merge events whose squared Euclidean distance is near to squared minimum Euclidean distance may be increased by employing MTC-CPFSK, compared to TC-CPFSK.

We introduce stepwise resonant excitation by two-color optical near fields in order to detect Rb atoms with a slit-type detector. Blue fluorescence of the second D2 line is monitored for background-free detection. Feasibility of the method is shown from an experiment with a Rb vapor cell, where a sub-Doppler spectrum with the FWHM of 80 MHz is obtained. The detection efficiency is estimated at about 3% for cold Rb atoms.

In this paper, we report on the transmission characteristics of transformers of a RF splitter widely used in CATV systems. From the point of view of broadening the splitter's operating frequency, the relationship between the RF transformer's transmission characteristics and design parameters has been investigated using computer-aided engineering. Based on the calculations, a sample device has been fabricated to confirm the theoretical results. It has been found that the configulation of the transformer winding is the most important factor affecting device performance. By selecting the appropriate winding, excessive loss can be suppressed to less than 1.6 dB and 3 dB in a frequency range of 20 MHz to 2,600 MHz for the cases of 2-way and 4-way splitters, respectively.