Variable 360° Vector-Sum Phase Shifter With Coarse and Fine Vector Scaling

A CMOS vector-sum phase shifter covering the full 360° range is presented in this paper. Broadband operational transconductance amplifiers with variable transconductance provide coarse scaling of the quadrature vector amplitudes. Fine scaling of the amplitudes is accomplished using a passive resistive network. Expressions are derived to predict the maximum bit resolution of the phase shifter from the scaling factor of the coarse and fine vector-scaling stages. The phase shifter was designed and fabricated using the standard 130-nm CMOS process and was tested on-wafer over the frequency range of 4.9–5.9 GHz. The phase shifter delivers root mean square (rms) phase and amplitude errors of 1.25° and 0.7 dB, respectively, at the midband frequency of 5.4 GHz. The input and output return losses are both below 17 dB over the band, and the insertion loss is better than 4 dB over the band. The circuit uses an area of 0.303 mm2 excluding bonding pads and draws 28 mW from a 1.2 V supply.

Coach Behaviors and Athlete Satisfaction in Team and Individual Sports

The coach can have a profound impact on athlete satisfaction, regardless of the level of sport involvement. Previous research has identified differences between coaching behavior preferences in team and individual sport athletes. The present study examined the moderating effect that an athlete's sport type (i.e., individual or team) may have on the relationships among seven coaching behaviors (mental preparation, technical skills, goal setting, physical training, competition strategies, personal rapport, and negative personal rapport) for predicting coaching satisfaction. Moderated multiple regression analyses indicated that each of the seven coaching behaviors were significant main effect predictors of coaching satisfaction. However, sport type (i.e., team or individual sports) was found to moderate six of the seven relationships: mental preparation, technical skills, goal setting, competition strategies, personal rapport, and negative personal rapport in predicting satisfaction with the coach. These findings indicate that high coaching satisfaction for athletes in team sports is influenced to a greater extent by the demonstration of these behaviors than it is for individual sport athletes.