A novel wide-range CMOS variable gain amplifier （VGA） topology is presented. The proposed VGA is composed of a variable transconductor and a novel variable output resistor and can offer a high gain variation range o...A novel wide-range CMOS variable gain amplifier （VGA） topology is presented. The proposed VGA is composed of a variable transconductor and a novel variable output resistor and can offer a high gain variation range of 80dB while using a single variable-gain stage. Temperature-compensation and decibel-linear gain characteristic are achieved by using a control circuit that provides a gain error lower than ±1.5dB over the full temperature and gain ranges. Realized in 0.25μm CMOS technology, a prototype of the proposed VGA provides a total gain range of 64.5dB with 55.6dB-linear range,a P-1dB varying from - 17.5 to 11.5dBm,and a 3dB-bandwith varying from 65 to 860MHz while dissipating 16.5mW from a 2.5V supply voltage.展开更多
In order to filter signal effectively according to selective center frequency, a voltage-controlled dynamic band-pass filter with gain compensation was designed based on voltage-controlled gain wideband amplifier VCA8...In order to filter signal effectively according to selective center frequency, a voltage-controlled dynamic band-pass filter with gain compensation was designed based on voltage-controlled gain wideband amplifier VCA810. The transfer function of the filter was analyzed and gain compensation voltages were given through tests; besides, a system was designed, including the gain compensation circuit and the control voltage circuit, etc. Center frequency will change from 1 kHz to 20 kHz according to control voltage on condition that bandwidth of the filter remains constant. The designed system has the advantages of simple structure, low noise, stable performance and convenient adjustment.展开更多
机顶盒(STB,Set Top Box)的概念是比较广泛的,从广义上讲,凡是电视机连接的网络终端设备都可称为机顶盒.从基于有线电视网络的模拟频道增补器、模拟频道解扰器,到将电话线与电视机联系在一起的"上网机顶盒"、数字卫星的综合...机顶盒(STB,Set Top Box)的概念是比较广泛的,从广义上讲,凡是电视机连接的网络终端设备都可称为机顶盒.从基于有线电视网络的模拟频道增补器、模拟频道解扰器,到将电话线与电视机联系在一起的"上网机顶盒"、数字卫星的综合接收解码器(IRD,Integrated Receive Decoder)、数字地面机顶盒、以及有线电视数字机顶盒都可称为机顶盒.从狭义上说,我们可以将模拟设备排除在外,按主要功能将机顶盒分为上网机顶盒、IP机顶盒、数字卫星综合接收解码器、数字地面机顶盒、以及有线电视数字机顶盒.展开更多
文摘A novel wide-range CMOS variable gain amplifier （VGA） topology is presented. The proposed VGA is composed of a variable transconductor and a novel variable output resistor and can offer a high gain variation range of 80dB while using a single variable-gain stage. Temperature-compensation and decibel-linear gain characteristic are achieved by using a control circuit that provides a gain error lower than ±1.5dB over the full temperature and gain ranges. Realized in 0.25μm CMOS technology, a prototype of the proposed VGA provides a total gain range of 64.5dB with 55.6dB-linear range,a P-1dB varying from - 17.5 to 11.5dBm,and a 3dB-bandwith varying from 65 to 860MHz while dissipating 16.5mW from a 2.5V supply voltage.
文摘In order to filter signal effectively according to selective center frequency, a voltage-controlled dynamic band-pass filter with gain compensation was designed based on voltage-controlled gain wideband amplifier VCA810. The transfer function of the filter was analyzed and gain compensation voltages were given through tests; besides, a system was designed, including the gain compensation circuit and the control voltage circuit, etc. Center frequency will change from 1 kHz to 20 kHz according to control voltage on condition that bandwidth of the filter remains constant. The designed system has the advantages of simple structure, low noise, stable performance and convenient adjustment.
文摘机顶盒(STB,Set Top Box)的概念是比较广泛的,从广义上讲,凡是电视机连接的网络终端设备都可称为机顶盒.从基于有线电视网络的模拟频道增补器、模拟频道解扰器,到将电话线与电视机联系在一起的"上网机顶盒"、数字卫星的综合接收解码器(IRD,Integrated Receive Decoder)、数字地面机顶盒、以及有线电视数字机顶盒都可称为机顶盒.从狭义上说,我们可以将模拟设备排除在外,按主要功能将机顶盒分为上网机顶盒、IP机顶盒、数字卫星综合接收解码器、数字地面机顶盒、以及有线电视数字机顶盒.
