- 您現在的位置：買賣IC網 > PDF目錄361030 > LM565 (National Semiconductor Corporation) Phase Locked Loop PDF資料下載
參數資料
| 型號： | LM565 |
| 廠商： | National Semiconductor Corporation |
| 英文描述： | Phase Locked Loop |
| 中文描述： | 鎖相環 |
| 文件頁數： | 8/11頁 |
| 文件大小： | 432K |
| 代理商： | LM565 |
Applications Information
In designing with phase locked loops such as the LM565, the
important parameters of interest are:
FREE RUNNING FREQUENCY
LOOP GAIN: relates the amount of phase change between
the input signal and the VCO signal for a shift in input signal
frequency (assuming the loop remains in lock). In servo
theory, this is called the “velocity error coefficient.”
The loop gain of the LM565 is dependent on supply voltage,
and may be found from:
f
o
= VCO frequency in Hz
V
c
= total supply voltage to circuit
Loop gain may be reduced by connecting a resistor between
pins 6 and 7; this reduces the load impedance on the output
amplifier and hence the loop gain.
HOLD IN RANGE: the range of frequencies that the loop will
remain in lock after initially being locked.
f
o
= free running frequency of VCO
V
c
= total supply voltage to the circuit
THE LOOP FILTER
In almost all applications, it will be desirable to filter the sig-
nal at the output of the phase detector (pin 7); this filter may
take one of two forms:
A simple lag filter may be used for wide closed loop band-
width applications such as modulation following where the
frequency deviation of the carrier is fairly high (greater than
10%), or where wideband modulating signals must be fol-
lowed.
The natural bandwidth of the closed loop response may be
found from:
Associated with this is a damping factor:
For narrow band applications where a narrow noise band-
width is desired, such as applications involving tracking a
slowly varying carrier, a lead lag filter should be used. In gen-
eral, if 1/R
C
<
K
K
, the damping factor for the loop be-
comes quite small resulting in large overshoot and possible
instability in the transient response of the loop. In this case,
the natural frequency of the loop may be found from
R
is selected to produce a desired damping factor
δ
, usually
between 0.5 and 1.0. The damping factor is found from the
approximation:
δ
)
π τ
2
f
n
These two equations are plotted for convenience.
Simple Lead Filter
DS007853-11
Lag-Lead Filter
DS007853-12
Filter Time Constant vs Natural Frequency
DS007853-13
www.national.com
8
相關PDF資料 |
PDF描述 |
|---|---|
| LM565C | |
| LM565CH | Analog Phase-Locked Loop |
| LM565CN | Phase Locked Loop |
| LM565H | CAP 63V 330UF ELECT AXIAL |
| LM566 | LM566C Voltage Controlled Oscillator |
相關代理商/技術參數 |
參數描述 |
|---|---|
| LM565C | 制造商:未知廠家 制造商全稱:未知廠家 功能描述: |
| LM565CH | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Analog Phase-Locked Loop |
| LM565CN | 制造商:Texas Instruments 功能描述:IC PHASE LOCKED LOOP DIP14 565 |
| LM565CN | 制造商:Texas Instruments 功能描述:IC PHASE LOCKED LOOP DIP14 565 |
| LM565CN/A+ | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Analog Phase-Locked Loop |
發布緊急采購，3分鐘左右您將得到回復。