• 易迪拓培训,专注于微波、射频、天线设计工程师的培养
首页 > 手机设计 > 手机射频设计讨论 > Transmitter architectures and .

Transmitter architectures and .

录入:edatop.com     点击:
HFE0605_McCambridgeandWhitaker.pdf :

点击下载...

Combination Closed Loop
and VCC Power Control for
a GSM/GPRS PA
By Paul McCambridge, Xindium Technologies, and
Brian Whitaker, Maxim Integrated Products
Power control is an
important performance
specification
for GSM/GPRS wireless
handsets. This article
shows how the MAX4002
low-cost, low-power logarithmic
amplifier and
power detector, and the XIN9133 quad-band
GSM/GPRS power amplifier (PA) are combined
in a closed loop power control system
with the added advantage of PA protection
through supply voltage power control. This
results in significant advantages over today’s
predominant GSM power control solutions on
the market.
Power Control Requirements
Important requirements for power amplifiers
in a GSM cell phone are:
? Adjustable and precision-set output power.
? The PA is not allowed to transmit outside its
frequency band (a precise power ramp control
is needed to eliminate out-of-band noise).
? The PA is only allowed to transmit in its
own timeslot, not in others (requiring tight
ramp control).
When a PA is used without control, it is difficult
to meet the GSM specifications, because
the PA by itself is not accurate enough.
Reasons for inaccuracy include:
? The PA is a non-linear device.
? The PA gain and output power varies with
frequency, battery voltage and temperature.
? Gain control slopes of PAs vary across device
populations.
There

Combination Closed Loop
and VCC Power Control for
a GSM/GPRS PA
By Paul McCambridge, Xindium Technologies, and
Brian Whitaker, Maxim Integrated Products
Power control is an
important performance
specification
for GSM/GPRS wireless
handsets. This article
shows how the MAX4002
low-cost, low-power logarithmic
amplifier and
power detector, and the XIN9133 quad-band
GSM/GPRS power amplifier (PA) are combined
in a closed loop power control system
with the added advantage of PA protection
through supply voltage power control. This
results in significant advantages over today’s
predominant GSM power control solutions on
the market.
Power Control Requirements
Important requirements for power amplifiers
in a GSM cell phone are:
? Adjustable and precision-set output power.
? The PA is not allowed to transmit outside its
frequency band (a precise power ramp control
is needed to eliminate out-of-band noise).
? The PA is only allowed to transmit in its
own timeslot, not in others (requiring tight
ramp control).
When a PA is used without control, it is difficult
to meet the GSM specifications, because
the PA by itself is not accurate enough.
Reasons for inaccuracy include:
? The PA is a non-linear device.
? The PA gain and output power varies with
frequency, battery voltage and temperature.
? Gain control slopes of PAs vary across device
populations.
There.........

申明:网友回复良莠不齐,仅供参考。

上一篇:有谁知道墨西哥的手机网络是用的是什么网络,是什么频段的?
下一篇:射频工具ISIS 2.02 使用指南

手机天线设计培训教程详情>>

手机天线设计培训教程 国内最全面、系统、专业的手机天线设计培训课程,没有之一;是您学习手机天线设计的最佳选择...【More..

易迪拓培训课程列表详情>>

我们是来自于研发一线的资深工程师,专注并致力于射频、微波和天线设计工程师的培养。

  网站地图