A visible-light-driven carboxylation of aryl and alkenyl triflates with CO 2 is developed by using a combination of Pd and photoredox catalysts. This reaction proceeds under mild conditions and can be applied to a wide range of substrates including acyclic alkenyl triflates.
This paper presents a wideband low-noise amplifier (LNA) architecture that is scalable in terms of the chip area and supply voltage and therefore is expected to offer superior performance with technology scaling. In order to secure lowvoltage scalability and allow for potential rail-to-rail operation under an ultralow supply voltage, the CMOS inverter is chosen as the basic amplifier stage. The core of the LNA gain stage comprises two CMOS inverters. To realize wideband operation with area scalability, two band broadening techniques that require neither inductors nor capacitors are adopted. First, to reduce the Miller capacitance, the classic Cherry-Hooper band broadening technique is applied to the CMOS inverterbased amplifier. Second, an active frequency peaking technique is introduced with the use of feedback through another CMOS inverter. The scalability and wideband characteristics of the proposed LNA are confirmed by comparing chips fabricated using 180 nm and 90 nm CMOS process technologies. The LNA in 90 nm CMOS achieved 18.0 dB gain, 0.1-6.8 GHz bandwidth, 3.0-5.5 dB noise figure, and 14.5 mW power dissipation with occupying only 0.0032 mm 2 , which is 48 % of the 180 nm CMOS LNA area.
Absrtact: This paper presents a new scheme of direct conversion phase shift keying (PSK) receivers applicable to time division multiple access (TDMA) land mobile communication systems. In the scheme, a matched filter in each I and Q channel is divided into two parts in front and at the back of a baseband amplifier to reduce baseband noise power and improve sensitivity. A rational design method to divide the filter is proposed; the filter cell that has narrowest equivalent noise bandwidth in the filter is chosen as the back part, while the remainder constitutes the front part. Moreover, memories are employed to eliminate DC offset in baseband signals. Experimental results show that, when applied to Personal Handy Phone System (PHS), a receiver employing the scheme achieves sensitivity comparable to that of a super-heterodyne receiver in continuous and burst reception.
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