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參數資料
| 型號： | ADF7020BCP |
| 廠商： | ANALOG DEVICES INC |
| 元件分類： | 無繩電話/電話 |
| 英文描述： | High Performance ISM Band FSK/ASK Transceiver IC |
| 中文描述： | TELECOM, CELLULAR, RF AND BASEBAND CIRCUIT, QCC48 |
| 封裝： | 7 X 7 MM, LFCSP-48 |
| 文件頁數： | 19/40頁 |
| 文件大小： | 797K |
| 代理商： | ADF7020BCP |
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Preliminary Technical Data
ADF7020
LINEAR FSK DEMODULATOR
A block diagram of the linear FSK demodulator is shown in
Figure 17.
Rev. PrH | Page 19 of 40
A
F
E
D
SLICER
FREQUENCY
IF
LEVEL
I
Q
LIMITER
7
MUX 1
ADC RSSI OUTPUT
LINEAR DISCRIMINATOR
DB(6:15)
FREQUENCY
READBACK
AND
AFC LOOP
Rx DATA
0
Figure 17. Block Diagram of Frequency Measurement System and
ASK.OOK/Linear FSK Demodulator
This method of frequency demodulation is useful when very
short preamble length is required and the system protocol
cannot support the overhead of the settling time of the internal
feedback AFC loop settling.
A digital frequency discriminator provides an output signal that
is linearly proportional to the frequency of the limiter outputs.
The discriminator output is then filtered and averaged using a
combined averaging filter and envelope detector. The demodu-
lated FSK data is recovered by threshold-detecting the output of
the averaging filter, as shown in Figure 17. In this mode, the
slicer output shown in Figure 17 is routed to the data synchro-
nizer PLL for clock synchronization. To enable the linear FSK
demodulator, set Bits R4_DB(4:5) to [00].
The 3 dB bandwidth of the postdemodulation filter is set in the
same way as the FSK correlator/demodulator, which is set in
R4_DB(6:15) and is defined as
CLK
DEMOD
F
Setting
BW
Demod
Post
CUTOFF
_
2
2
_
_
_
10
×
π
×
=
where:
F
CUTOFF
is the target 3 dB bandwidth in Hz of the
postdemodulator filter.
DEMOD_CLK
is as defined in the Register 3—Receiver Clock
Register section, Note 2.
ASK/OOK Operation
ASK/OOK demodulation is activated by setting Bits
R4_DB(4:5) to [10].
Digital filtering and envelope detecting the digitized RSSI input
via MUX 1, as shown in Figure 17, perform ASK/OOK
demodulation. The bandwidth of the digital filter must be
optimized to remove any excess noise without causing ISI in the
received ASK/OOK signal.
The 3 dB bandwidth of this filter is typically set at approxi-
mately 0.75 times the user data rate and is assigned by R4
_DB(6:15) as
Post_Demod_BW_Setting
=
DEMOD_CLK
F
CUTOFF
×
π
×
2
2
10
where
F
CUTOFF
is the target 3 dB bandwidth in Hz of the
postdemodulator filter.
AFC SECTION
The ADF7020 supports a real-time AFC loop, which is used to
remove frequency errors that can arise due to mismatches
between the transmit and receive crystals. This uses the
frequency discriminator block, as described in the Linear FSK
Demodulator section (see Figure 17). The discriminator output
is filtered and averaged to remove the FSK frequency
modulation using a combined averaging filter and envelope
detector. In FSK mode, the output of the envelope detector
provides an estimate of the average IF frequency.
Two methods of AFC, external and internal, are supported on
the ADF7020 (in FSK mode only).
External AFC
The user reads back the frequency information through the
ADF7020 serial port and applies a frequency correction value to
the fractional-N synthesizer’s N divider.
The frequency information is obtained by reading the 16-bit
signed AFC_readback, as described in the Readback Format
section, and applying the following formula:
FREQ_RB
[Hz] = (
AFC_READBACK
×
DEMOD_CLK
)/2
15
Note that while the
AFC_READBACK
value is a signed number,
under normal operating conditions it is positive. In the absence
of frequency errors, the FREQ_RB value is equal to the IF
frequency of 200 kHz.
Internal AFC
The ADF7020 supports a real-time internal automatic
frequency control loop. In this mode, an internal control loop
automatically monitors the frequency error and adjusts the
synthesizer N divider using an internal PI control loop.
The internal AFC control loop parameters are controlled in
Register 11. The internal AFC loop is activated by setting
R11_DB20 to 1. A scaling coefficient must also be entered,
based on the crystal frequency in use. This is set up in
R11_DB(4:19) and should be calculated using
AFC_Scaling_Coefficient
= (500 × 2
24
)/
XTAL
Therefore, using a 10 MHz XTAL yields an AFC scaling
coefficient of 839.
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| ADF7020BCP-REEL | 制造商:Analog Devices 功能描述:RF TRNSCVR ASK/FSK 2.5V/3.3V 48LFCSP EP - Tape and Reel |
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| ADF7020BCP-U1 | 制造商:Analog Devices 功能描述:HIGH PERFORMANCE ISM BAND FSK/ASK TRANSCEIVER IC - Trays |
| ADF7020BCPZ | 功能描述:IC TX FSK/ASK ISM BAND 48LFCSP RoHS:是 類別:RF/IF 和 RFID >> RF 收發器 系列:- 產品培訓模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標準包裝:30 系列:- 頻率:4.9GHz ~ 5.9GHz 數據傳輸率 - 最大:54Mbps 調制或協議:* 應用:* 功率 - 輸出:-3dBm 靈敏度:- 電源電壓:2.7 V ~ 3.6 V 電流 - 接收:* 電流 - 傳輸:* 數據接口:PCB，表面貼裝 存儲容量:- 天線連接器:PCB，表面貼裝 工作溫度:-25°C ~ 85°C 封裝/外殼:68-TQFN 裸露焊盤 包裝:管件 |
| ADF7020BCPZ-RL | 功能描述:IC TX FSK/ASK ISM BAND 48LFCSP RoHS:是 類別:RF/IF 和 RFID >> RF 收發器 系列:- 產品培訓模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標準包裝:30 系列:- 頻率:4.9GHz ~ 5.9GHz 數據傳輸率 - 最大:54Mbps 調制或協議:* 應用:* 功率 - 輸出:-3dBm 靈敏度:- 電源電壓:2.7 V ~ 3.6 V 電流 - 接收:* 電流 - 傳輸:* 數據接口:PCB，表面貼裝 存儲容量:- 天線連接器:PCB，表面貼裝 工作溫度:-25°C ~ 85°C 封裝/外殼:68-TQFN 裸露焊盤 包裝:管件 |
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