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參數(shù)資料
| 型號(hào)： | LC72147V |
| 廠商： | Sanyo Electric Co.,Ltd. |
| 英文描述： | PLL Frequency Synthesizer for Electronic Tuning in Car Audio Systems |
| 中文描述： | 鎖相環(huán)頻率合成器在汽車音響系統(tǒng)的電子調(diào)諧 |
| 文件頁數(shù)： | 20/22頁 |
| 文件大?。?/td> | 154K |
| 代理商： | LC72147V |
When a dead band is present (OFF/OFF mode), the loop will be stable, but it will be harder to acquire a good C/N ratio.
On the other hand, with the mode that does not have a dead band (ON/ON mode), it will be easier to acquire a high C/N
ratio, but harder to acquire loop stability.
Therefore, the DZA and DZB modes, in which there is no dead band, can be effective if either a high signal-to-noise ratio
of 90 to 100 dB in FM reception or an increased pilot margin in AM stereo reception is required.
Inversely, if such a high FM signal-to-noise ratio is not required for FM reception, or an adequate pilot margin can be
acquired for AM stereo reception, then the DZC and DZD modes, in which a dead band is present, may be more
effective.
Dead zone (dead band) definition
The phase comparator compares fp with the reference frequency (fr) as shown in figure 1. This circuit outputs a voltage
V (A) that is proportional to the phase difference as shown in figure 2. However, due to internal delays and other
factors, the actual IC is unable to compare small phase differences, and thus a dead zone (B) appears in the output. To
achieve a high signal-to-noise ratio in the end product, the dead zone should be as small as possible.
However, in popularly-priced models, there are cases where a somewhat wider dead zone may be easier to work with.
This is because in some situations, such as when a powerful signal is applied to the RF input, in popularly-priced models
there may be RF leakage from the mixer to the VCC. When the dead zone is narrow, outputs to correct this leakage are
output, that output in turn modulates the VCO, and generates a beat signal with the RF.
(2) Notes on the FMIN and HCTR pins
The coupling capacitor must be located as close as possible to these pins. A capacitance of approximately 100 pF is
desirable.
In particular, if the HCTR pin capacitor is over about 1000 pF, the time required to reach the bias level may become
excessive, and incorrect counting may occur due to the relationship with the wait time.
(3) Notes on the IF counting
→
SD must be used in conjunction with IF counting.
If the general-purpose counter is used to count the IF frequency, the application microcontroller must test the state of the
IF IC SD (station detect) signal, and only if the SD signal is present, turn on the IF counter buffer output and perform an
IF count operation. Methods in which auto-search operations are implemented only using the IF count may incorrectly
stop at frequencies where no station is present due to leakage from the IF counter buffer.
(4) Using the DO pin
At times other than data output mode, the DO pin can also be used to check for general-purpose counter count operation
completion, to output the unlock state detection signal, and to check for changes in the input pins.
Note that the states of the input pins (I/O-1 and I/O-2) can be directly input to the system microcontroller through the DO
pin.
(5) Power supply pins
Capacitors of over 2000 pF must be inserted between the VDD and VSS power supply pins and between Vreg and VSS
to reduce noise. These capacitors must be located as close to the VDD, Vreg, and VSS pins as possible.
No. 6675-20/22
LC72147V
Reference divider
Programmable divider
VCO
LPF
Phase
detector
MIX
RF
Leakage
fr
fp
(nsec)
(B)
(A)
Dead zone
Figure 1
Figure 2
相關(guān)PDF資料 |
PDF描述 |
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| LC72148V | Electronic Tuning PLL Frequency Synthesizer for Car Stereo Systems |
| LC7215 | MW/LW PLL Frequency Synthesizers |
| LC7215F | MW/LW PLL Frequency Synthesizers |
| LC7215FM | MW/LW PLL Frequency Synthesizers |
| LC7216M | PLL Frequency Synthesizer for Electronic Tuning |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LC72148V | 制造商:SANYO 制造商全稱:Sanyo Semicon Device 功能描述:Electronic Tuning PLL Frequency Synthesizer for Car Stereo Systems |
| LC72148V-MPB-E | 制造商:ON Semiconductor 功能描述:PLL FREQUENCY SYNTHESIZER - Ammo Pack 制造商:ON Semiconductor 功能描述:Phase Locked Loops - PLL |
| LC72148V-TLM-E | 功能描述:時(shí)鐘合成器/抖動(dòng)清除器 RoHS:否 制造商:Skyworks Solutions, Inc. 輸出端數(shù)量: 輸出電平: 最大輸出頻率: 輸入電平: 最大輸入頻率:6.1 GHz 電源電壓-最大:3.3 V 電源電壓-最小:2.7 V 封裝 / 箱體:TSSOP-28 封裝:Reel |
| LC7215 | 制造商:SANYO 制造商全稱:Sanyo Semicon Device 功能描述:MW/LW PLL Frequency Synthesizers |
| LC72151V | 制造商:SANYO 制造商全稱:Sanyo Semicon Device 功能描述:PLL Frequency Synthesizer for Electronic Tuning in Car Audio Systems |
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