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參數(shù)資料
| 型號： | VCA810AIDR |
| 英文描述： | High Gain Adjust Range, Wideband, Voltage-Controlled Amplifier |
| 中文描述： | 高增益調整范圍，寬帶，電壓控制放大器 |
| 文件頁數(shù)： | 13/25頁 |
| 文件大小： | 417K |
| 代理商： | VCA810AIDR |
"#$%
SBOS275C JUNE 2003 REVISED OCTOBER 2004
www.ti.com
13
STABILIZED WEIN-BRIDGE OSCILLATOR
Adding Wein-bridge feedback to the above AGC amplifier
produces an amplitude-stabilized oscillator. As Figure 6
shows, this alternative requires the addition of just two
resistors (R
W1
, R
W2
) and two capacitors (C
W1
, C
W2
).
Connecting the feedback network to the amplifier
non-inverting input introduces positive feedback to induce
oscillation. The feedback factor displays a frequency
dependence due to the changing impedances of the C
W
capacitors. As frequency increases, the decreasing
impedance of the C
W2
capacitor increases the feedback
factor. Simultaneously, the decreasing impedance of the
C
W1
decreases this factor. Analysis shows that the
maximum factor occurs at
f
W
1
2
R
W
C
W
Hz, making
this the frequency most conducive to oscillation. At this
frequency, the impedance magnitude of C
W
equals R
W
,
and inspection of the circuit shows that this condition
produces a feedback factor of 1/3. Thus, self-sustaining
oscillation requires a gain of three through the amplifier.
The AGC circuitry establishes this gain level. Following
initial circuit turn-on, R
1
begins charging C
H
negative,
increasing the amplifier gain from its minimum. When this
gain reaches three, oscillation begins at f
W
; the continued
charging effect of R
1
makes the oscillation amplitude grow.
This growth continues until that amplitude reaches a peak
value equal to V
R
. Then, the AGC circuit counteracts the
R
1
effect, controlling the peak amplitude at V
R
by holding
the amplifier gain at a level of three. Making V
R
an AC
signal, rather than a DC reference, produces amplitude
modulation of the oscillator output.
VCA810
C
H
1
μ
F
V
OPA820
V
0.1 VDC
V
OPEAK
= V
R
V
O
R
3
1k
HP5082
R
1
50k
C
4700pF
R
4
100
R
2
50k
R
300
R
W2
300
C
4700pF
C
10pF
f = 1/2
π
R
W1
C
W1
R
W1
= R
W2
C
W1
= C
W2
V
C
Figure 6. Amplitude-Stabilized Oscillator
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相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| VCA810AIDRG4 | 功能描述:特殊用途放大器 High-Gain Adj Range Wideband Vltg-Cntrl RoHS:否 制造商:Texas Instruments 通道數(shù)量:Single 共模抑制比（最小值）: 輸入補償電壓: 工作電源電壓:3 V to 5.5 V 電源電流:5 mA 最大功率耗散: 最大工作溫度:+ 70 C 最小工作溫度:- 40 C 安裝風格:SMD/SMT 封裝 / 箱體:QFN-20 封裝:Reel |
| VCA810ID | 功能描述:特殊用途放大器 High-Gain Adj Range Wideband Vltg-Cntrl RoHS:否 制造商:Texas Instruments 通道數(shù)量:Single 共模抑制比（最小值）: 輸入補償電壓: 工作電源電壓:3 V to 5.5 V 電源電流:5 mA 最大功率耗散: 最大工作溫度:+ 70 C 最小工作溫度:- 40 C 安裝風格:SMD/SMT 封裝 / 箱體:QFN-20 封裝:Reel |
| VCA810IDG4 | 功能描述:特殊用途放大器 High-Gain Adj Range Wideband Vltg-Cntrl RoHS:否 制造商:Texas Instruments 通道數(shù)量:Single 共模抑制比（最小值）: 輸入補償電壓: 工作電源電壓:3 V to 5.5 V 電源電流:5 mA 最大功率耗散: 最大工作溫度:+ 70 C 最小工作溫度:- 40 C 安裝風格:SMD/SMT 封裝 / 箱體:QFN-20 封裝:Reel |
| VCA810IDR | 功能描述:特殊用途放大器 High-Gain Adj Range Wideband Vltg-Cntrl RoHS:否 制造商:Texas Instruments 通道數(shù)量:Single 共模抑制比（最小值）: 輸入補償電壓: 工作電源電壓:3 V to 5.5 V 電源電流:5 mA 最大功率耗散: 最大工作溫度:+ 70 C 最小工作溫度:- 40 C 安裝風格:SMD/SMT 封裝 / 箱體:QFN-20 封裝:Reel |
| VCA810IDRG4 | 功能描述:特殊用途放大器 High-Gain Adj Range Wideband Vltg-Cntrl RoHS:否 制造商:Texas Instruments 通道數(shù)量:Single 共模抑制比（最小值）: 輸入補償電壓: 工作電源電壓:3 V to 5.5 V 電源電流:5 mA 最大功率耗散: 最大工作溫度:+ 70 C 最小工作溫度:- 40 C 安裝風格:SMD/SMT 封裝 / 箱體:QFN-20 封裝:Reel |
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