signal 訊號/信號
system 系統
analog signal 類比訊號 x(t)
continuous-time signal 連續時間訊號 = Analog Signals
discrete-time signal 離散時間訊號 x[n]
digital signal 數位訊號 - both time and value are discrete. 時間及數值皆為不連續時的訊號
periodic signal 週期訊號 x(t) = x(t + T) where T = duration of period
aperiodic signal / non-periodic signal 非週期訊號
difference equation 差分方程式
constant-coefficient 常係數
liner constant-coefficient difference equation 線性常係數差分方程式
derivative 導數/衍生物
參考資料
國家教育研究院雙語詞彙、學術名詞暨辭書資訊網
MIT Discrete-time signal processing course (Week 1 T1.1 3:00) (edX)
2016/08/26
Signals and Systems 訊號與系統
Input-Process-Output (IPO) model
Analog Signal Processing System:
Input: Analog Signal
Process: Analog Signal Processor
Output: Analog Signal
Digital Signal Processing System:
Input: Analog Signal
Process: ADC -> Digital Signal Processor -> DAC
Output: Analog Signal
Transfer Function/System Function - used to represent the black box mathematically.
transfer function 轉換函數/轉移函數/傳遞函數
system function 系統函數
represented as H().
And h is the impulse response of the system.
Example:
system function H(z)
impulse response h[n]
For a system H(z) = Y(z) / X(z) => y[n] = h[n] * x[n]
Since the z-transform of an impulse signal is δ(z) = Σδ[n]z-n = 1,
the impulse response is h[n]:
Y(z) = H(z)X(z) = H(z)δ(z) = H(z) ====z-1====> h[n]
In terms of Fourier transform, the impulse response is h[n] = F-1{H(ejω)}
For an LTI system:
Continuous-Time Signal 連續時間訊號
input - x(t)
output - y(t)
system - H(s) => H(jΩ) (Frequency Domain 頻域)
y(t) = h(t) * x(t)
H(s) = Y(s)/X(s)
Discrete-Time Signal 離散時間訊號
input - x[n]
output - y[n]
system - H(z) => H(ejω) (Frequency Domain 頻域)
y[n] = h[n] * x[n]
H(z) = Y(z)/X(z)
Discrete-time Signal Processing (2nd edition) by A. Oppenheim:
2.1 Basic Sequences and Sequence Operations
Unit sample sequence: 𝛿[n]
Unit step sequence: u[n]
Exponential sequence: x[n] = Aαn
Sinusoidal sequence: x[n] = Acos(ω0n+φ)
impulse function 脈衝函數
delta function δ函數
Transfer function H(ejω)
- mathematical expression for a system
- can be used to derive frequency response including (1) magnitude response (2) phase response
Diagram of (1) and (2) is called the Bode plot 波德圖
impulse response 脈衝響應
frequency response 頻率響應
magnitude response 振幅響應
gain 增益
phase response 相位響應
phase shift 相移/相位偏移
if magnitude and phase output of a system is not changed as desired, there are:
magnitude distortion 振幅失真
phase distortion 相位失真
group delay 群延/群延遲/群組延遲/群體延遲
analytical signal 分析訊號/解析訊號 - complex function without negative frequency.
Analog Signal Processing System:
Input: Analog Signal
Process: Analog Signal Processor
Output: Analog Signal
Digital Signal Processing System:
Input: Analog Signal
Process: ADC -> Digital Signal Processor -> DAC
Output: Analog Signal
Transfer Function/System Function - used to represent the black box mathematically.
transfer function 轉換函數/轉移函數/傳遞函數
system function 系統函數
represented as H().
And h is the impulse response of the system.
Example:
system function H(z)
impulse response h[n]
For a system H(z) = Y(z) / X(z) => y[n] = h[n] * x[n]
Since the z-transform of an impulse signal is δ(z) = Σδ[n]z-n = 1,
the impulse response is h[n]:
Y(z) = H(z)X(z) = H(z)δ(z) = H(z) ====z-1====> h[n]
In terms of Fourier transform, the impulse response is h[n] = F-1{H(ejω)}
For an LTI system:
Continuous-Time Signal 連續時間訊號
input - x(t)
output - y(t)
system - H(s) => H(jΩ) (Frequency Domain 頻域)
y(t) = h(t) * x(t)
H(s) = Y(s)/X(s)
Discrete-Time Signal 離散時間訊號
input - x[n]
output - y[n]
system - H(z) => H(ejω) (Frequency Domain 頻域)
y[n] = h[n] * x[n]
H(z) = Y(z)/X(z)
Discrete-time Signal Processing (2nd edition) by A. Oppenheim:
2.1 Basic Sequences and Sequence Operations
Unit sample sequence: 𝛿[n]
Unit step sequence: u[n]
Exponential sequence: x[n] = Aαn
Sinusoidal sequence: x[n] = Acos(ω0n+φ)
impulse function 脈衝函數
delta function δ函數
Transfer function H(ejω)
- mathematical expression for a system
- can be used to derive frequency response including (1) magnitude response (2) phase response
Diagram of (1) and (2) is called the Bode plot 波德圖
impulse response 脈衝響應
frequency response 頻率響應
magnitude response 振幅響應
gain 增益
phase response 相位響應
phase shift 相移/相位偏移
if magnitude and phase output of a system is not changed as desired, there are:
magnitude distortion 振幅失真
phase distortion 相位失真
group delay 群延/群延遲/群組延遲/群體延遲
analytical signal 分析訊號/解析訊號 - complex function without negative frequency.
2016/08/20
Bluetooth Audio Profiles 與聲音有關的藍牙規範/描述檔
For Audio Streaming (Single-directional)
A2DP (Advanced Audio Distribution Profile) - high quality audio streaming.
AVRCP (Audio/Video Remote Control Profile) - control A/V equipment. Used with A2DP or VDP (Video Distribution Profile).
GAVDP (Generic Audio/Video Distribution Profile) - basis for A2DP and VDP streaming.
For Mobile Phones (Bi-directional)
HSP (Headset Profile) - for headsets to communicate with mobile phones.
HFP (Hands-Free Profile) - for communication between hands-free devices and mobile phones in the car. With extended features to HSP.
More Information:
Differences between HSP & HFP
For Audio Streaming
CTP (Cordless Telephony Profile) - for cordless phones.
參考資料
藍牙規範(維基百科)
如何選購藍芽耳機
A2DP (Advanced Audio Distribution Profile) - high quality audio streaming.
AVRCP (Audio/Video Remote Control Profile) - control A/V equipment. Used with A2DP or VDP (Video Distribution Profile).
GAVDP (Generic Audio/Video Distribution Profile) - basis for A2DP and VDP streaming.
For Mobile Phones (Bi-directional)
HSP (Headset Profile) - for headsets to communicate with mobile phones.
HFP (Hands-Free Profile) - for communication between hands-free devices and mobile phones in the car. With extended features to HSP.
More Information:
Differences between HSP & HFP
For Audio Streaming
CTP (Cordless Telephony Profile) - for cordless phones.
參考資料
藍牙規範(維基百科)
如何選購藍芽耳機
2016/08/15
Matlab: Clear Commands
Clear Command Window: clc
Clear Workspace: clear
Clear a variable: clear variableName
Clear Workspace: clear
Clear a variable: clear variableName
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