关于8960衰减的设置

gook2009

以下是引用skywood在2010-9-13 17:09:27的发言：
800M -0.5 1800M -0.8 差了1000M才差了0.3dB。100M也就0.03dB左右。你研究那么透彻干什么？会影响你的测试指标？
低频情况下线缆损耗可以按频率线性计算。到2G以上才损耗才有可能产生非线性变化。要想知道怎么变去看射频电缆生产厂家提供的数据曲线。

上次有个客户这样问，所以想弄清楚，安捷伦是怎么定义8960那个补偿的设置的。
我说的不是是怎么损耗的，我是问安捷伦怎么定义各个频点的损耗补偿的。比如说我设900MHZ的损耗是0.5db，那它指的是900这一频点的损耗是0.5，还是其它什么？

skywood

800M -0.5 1800M -0.8 差了1000M才差了0.3dB。100M也就0.03dB左右。你研究那么透彻干什么？会影响你的测试指标？
低频情况下线缆损耗可以按频率线性计算。到2G以上才损耗才有可能产生非线性变化。要想知道怎么变去看射频电缆生产厂家提供的数据曲线。

gook2009

晕  没一个人清楚的知道吗？   可恶的MTK……

gook2009

以下是引用wangzongcumt在2010-9-26 15:19:04的发言：
恩，这个问题很纠结，我也不知道，是那一个频点还是频率段的。但是要是每个频点的话，那800段的我记得都是设为0.5啊。。那岂不是0.5是这个频段的了？？

而不是单独的特定的频点。。。

纠结。。。。

而且每个频点设感觉又不现实。。好多点。。还有高频段                的。。仪器上的好像不够用的。。

所以一直没搞清楚，agient是怎么定义这个的。大家好像都不是很了解这个的，就是不知这儿有没有agient的工程师，给解释下。
[em02][em02]

viszl

线性插值。

bhz1979

正解！！！

xiaofanghui1983

G网一般有高中低3个信道的线损，只是取样而已，不能代表整个频带。

63835909

学习学习

gook2009

以下是引用charles_yen在2011-1-7 15:30:03的发言：
其实我觉得楼主可以设置夸张一点的补偿，看一下旁边的频点是怎么变化的

这个试过好多次   没找出规律来

试几次觉得是这种规律  但再不同的多试 又不是那个规律了  现在一直没搞清楚  问了好多人 好像没人清楚倒底什么？

charles_yen

其实我觉得楼主可以设置夸张一点的补偿，看一下旁边的频点是怎么变化的

ldsjkl

楼主你说的那个值就是从8960（CMU200)的射频端口出来到手机射频头这段距离cable线的损耗补偿。[em01]

a812681372

好的很啊！！！！！

myzod

cable loss

8960自动做线性插值的

nick230

学习中ing...

gook2009

以下是引用xwugui在2011-2-11 11:39:42的发言：
Amplitude Offsets Between Frequency Settings

If mobile station testing is performed at frequencies that do not have amplitude offsets assigned to them, the test set will estimate an amplitude offset based on the nearest settings. For example, the following screen shows five amplitude offsets for frequencies ranging from 890.2 MHz to 1710.2 MHz.
For test frequencies between the lowest (890.2 MHz) and highest (1710.2 MHz) frequency points that are not entered in the table, the test set will calculate offsets using piece-wise linear interpolation.

The graph shown in Amplitude Offset Interpolation is a conceptual representation of the test set's amplitude offset configuration using the settings from the RF IN/OUT Amplitude Offset table in RF IN/OUT Amplitude Offset Setup . Each of the five points are shown on a non-scaled frequency versus amplitude offset graph. At a test frequency of 890.4 MHz, which is midway between point number one (-1 dB) and point number two (-2 dB) the test set applies an offset of -1.5 dB. Be aware that since amplitude offsets are in units of dB, this piece-wise linear interpolation does not produce a linear transition from point to point.

Amplitude Offset Interpolation

If testing is done outside the range of frequencies bounded by the lowest and highest frequency entries, the test set simply uses the amplitude offset that is paired with the nearest frequency point.

IMPORTANT
--------------------------------------------------------------------------------

It is highly recommended that amplitude offsets are set up for each test frequency. This eliminates inaccuracies due to the mismatch between the test set's linear interpolation and the actual frequency response of the RF path between the test set and mobile station.

能不能给传个完整的资料

xwugui

Amplitude Offsets Between Frequency Settings

If mobile station testing is performed at frequencies that do not have amplitude offsets assigned to them, the test set will estimate an amplitude offset based on the nearest settings. For example, the following screen shows five amplitude offsets for frequencies ranging from 890.2 MHz to 1710.2 MHz.
For test frequencies between the lowest (890.2 MHz) and highest (1710.2 MHz) frequency points that are not entered in the table, the test set will calculate offsets using piece-wise linear interpolation.

The graph shown in Amplitude Offset Interpolation is a conceptual representation of the test set's amplitude offset configuration using the settings from the RF IN/OUT Amplitude Offset table in RF IN/OUT Amplitude Offset Setup . Each of the five points are shown on a non-scaled frequency versus amplitude offset graph. At a test frequency of 890.4 MHz, which is midway between point number one (-1 dB) and point number two (-2 dB) the test set applies an offset of -1.5 dB. Be aware that since amplitude offsets are in units of dB, this piece-wise linear interpolation does not produce a linear transition from point to point.

Amplitude Offset Interpolation

If testing is done outside the range of frequencies bounded by the lowest and highest frequency entries, the test set simply uses the amplitude offset that is paired with the nearest frequency point.

IMPORTANT
--------------------------------------------------------------------------------

It is highly recommended that amplitude offsets are set up for each test frequency. This eliminates inaccuracies due to the mismatch between the test set's linear interpolation and the actual frequency response of the RF path between the test set and mobile station.

gook2009

以下是引用myzod在2011-1-21 17:05:18的发言：
cable loss

8960自动做线性插值的

给详细说下撒

shichangyuan

是对应该频段的功率补偿  没有具体的值  经验值而已

djboychao

用网络分析仪做个频率扫描吧。[em01]