# 直流耦合和交流耦合的区别

The COUPLING pushbutton selects the method of connecting the A and B inputs to the amplifier. The inputs can be AC (0.03 Hz – 3 dB) or DC-coupled, or the inputs to the amplifier can be internally grounded with the A and B input BNC’s left floating. This feature makes for simple offset nulling, particularly useful when operating the amplifier DC-coupled at high gains. Please refer to CALIBRATION AND REPAIR — OFFSET ADJUSTMENT for information on the offset nulling procedure.

NOTE: When the coupling is set to AC, a 0.03 Hz cutoff high-pass filter is always engaged. All high-pass filter modes can still be selected while AC-coupled, but the 0.03 Hz filter will always be in, even if the filters are set to DC. Because one of the two filter sections is always used as a high pass when AC coupling is selected, low-pass filters are only available with a 6 dB / octave rolloff.

This key selects the input coupling. The signal input can be either AC or DC coupled. The current input is coupled after the current to voltage conversion. The current input itself is always DC coupled (1 kΩ to virtual ground).
The AC coupling high pass filter passes signals above 160 mHz and attenuates signals at lower frequencies. AC coupling should be used at frequencies above 160 mHz whenever possible. At lower frequencies, DC coupling is required. AC coupling results in gain and phase errors at low frequencies.
Remember, the Reference Input is AC coupled when a sine reference is used. This also results in phase errors at low frequencies.

# Sentaurus Structure Editor 学习笔记（1）

Sentaurus TCAD的结构编辑可以使用GUI，每一个操作都对应命令行，目前只用过编辑命令行.cmd文件，把遇到过的命令行记录一下

New Replaces Old，重叠处，已有的形状被减去
(sdegeo:set-default-boolean “ABA”)

Old Replaces New，重叠出，新建的形状被减去
(sdegeo:set-default-boolean “BAB”)

2017-03-08 术士

2017-05-20 猎人

2017-10-01 萨满

2018-02-11 德鲁伊

2018-09-24 法师

2018-10-04 战士

2018-10-13 盗贼

2018-11-4 骑士

# FDTD 计算发散解决方法

## 确定发散的类型

• 如果模拟仍然发散，这是一种dt稳定因子的发散。参见“dt稳定性系数”部分。
• 如果模拟稳定，则为PML型发散。参见PML和色散材料部分。

# 安装FDTD提示需要.net framework 2.0

控制面板程序和功能启用或关闭windows功能中，勾选.NET Framework3.5(包括.NET2.0 和 3.0)