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Saiwai ku, Japan

Kousai S.,Toshiba Corporation | Onizuka K.,Toshiba Corporation | Yamaguchi T.,Komukai Toshiba cho | Kuriyama Y.,Komukai Toshiba cho | Nagaoka M.,Komukai Toshiba cho
IEEE Journal of Solid-State Circuits | Year: 2012

A wideband feedback linearization technique for a power amplifier (PA), PA-closed loop, is presented. In order to achieve wideband operation, it employs a two-path feedback scheme where the input and output phases and amplitudes are detected at RF and compared to directly control and linearize the PA. The wideband characteristic of the loop suppressed the adjacent channel leakage ratio (ACLR) for WCDMA standard by 6 dB. The advantage of the feedback is demonstrated by measuring the performance against the load variation. The required back-off is degraded by only 1 dB with a voltage standing wave ratio (VSWR) of 1.5, whereas it is 3 dB without the loop. The loop consumes 28.3 mW and it reduces the quiescent power consumption of the PA by 78 mW. The chip, which integrates the loop and PA, is fabricated in a 0.13 μm CMOS technology and the loop occupies 0.3 mm by 0.7 mm. The PA delivers WCDMA output power of 27.1 dBm with a power added efficiency (PAE) of 28% and ACLR of 40 dBc. This topology makes possible the wideband feedback linearization of a watt-level PA. © 2012 IEEE.

Sato Y.,Komukai Toshiba cho | Oki M.,Komukai Toshiba cho | Kondo A.,Komukai Toshiba cho | Takenaka M.,Komukai Toshiba cho | Satake H.,Komukai Toshiba cho
Analytical Methods | Year: 2010

Novel rapid analytical method was developed for evaluating polymers for the presence of polybrominated diphenyl ethers (PBDEs), which have been prohibited by the RoHS directive, using ion attachment mass spectrometry (IAMS). IAMS requires no chemical pretreatment or separation process for the individual organic compounds before analysis because of its "soft" ionization feature. When measurement was performed for a standard solution of decabromodiphenly ether (decaBDE), no fragment ions were detected. The optimum analysis conditions for polymers were determined using reference materials. When polymers containing decaBDE were analyzed by IAMS under the optimum conditions, a decaBDE concentration of approximately 300 ppm (in the case of 1-mg solid sample for analysis) could be detected with no fragmentation. Even if other brominated compounds, such as ethylene (bis-tetrabromophthal)imide (EBTBPI) and bis(pentabromophenyl)ethane (BPBPE) were present in the sample together with decaBDE, each compound could be identified successfully. In addition, with respect to the validation of IAMS, it was confirmed the limit of detection (LOD) and the limit of quantification (LOQ) for decaBDE were 13.5 and 45.0 ppm (in the case of 1-mg solid sample for analysis), respectively, and that the calibration curve showed good linearity (R2 = 0.9962) within the range of 0.04 to 2.00 μg. The recovery of the decaBDE from the certified reference materials was 81.4% for the 317-ppm sample and 85.4% for 886-ppm sample. © 2010 The Royal Society of Chemistry.

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