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参数资料
| 型号： | WE905 |
| 厂商： | Electronic Theatre Controls, Inc. |
| 英文描述： | 0.1 - 1GHx Single Chip FM Transceiver |
| 中文描述： | 0.1 - 1GHx单芯片FM收发器 |
| 文件页数： | 39/39页 |
| 文件大小： | 623K |
| 代理商： | WE905 |
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Winceiver WE904/WE905
WiNEDGE & WiRELESS
0.1 - 1GHz Single Chip FM Transceiver
2003 WiNEDGE & WiRELESS PTE LTD
Page 9
Rev Date: 2003 May 27
The VCO center frequency is determined by an external tank circuit comprised of two inductors
connected to the TVCO pins 15 and 16. An external PLL loop filter network, connected to TPLL, pin
13, filters the VCO control voltage. This control voltage (KVCO 26 MHz/V for 900MHz) is used to tune
the tank frequency of the VCO via an internal, common-anode, varactor pair.
The transmit frequency for the WE904/905 is programmed via serial interface (Data, Clock, and Load
Enable).
PA
The on-chip RF power amplifier is a differential gain stage capable of transmitting RF output power up
to +4.5dBm.
The differential output impedance is ~ 700 //1.2 pF at 915MHz. In the simplified application circuit
shown in page 3, a discrete LC network is used to match the output impedance to 50
at 915MHz
ISM band. The 33 resistor set the output power to ~ +3dBm. A 82 resistor will reduce the power to
–10dBm.
REFERENCE OSCILLATOR
Crystal Oscillator and Reference Synthesizer
The reference synthesizer is comprised of an 11 bit counter which provides the PLL reference
frequency for both the receiver and transmitter synthesizers. A crystal oscillator circuit normally
provides the input to the reference synthesizer; however, external frequency source can be used as a
reference for the synthesizer. All 11 bits of the synthesizer are fully programmable, to allow a large
degree of flexibility in the choice of either the reference crystal or external reference frequency.
For WE905, this reference oscillator can be kept active when both Tx and RX are off, by
programming the Mode Register, and hence, reduce turn-on time for Tx or Rx. Whereas on WE904,
the reference clock will be off when both Tx and Rx are off.
AFC
Automatic Frequency Control (AFC) of the receive local oscillator (LO) frequency is used to improve
receiver performance. Without AFC, frequency offset (between receive signal and LO) causes a
reduction in SINAD due to filter distortion and beat tone. The AFC minimized the offset by tuning the
reference crystal oscillator. As a result, both transmit frequency and the receive LO are corrected at
the same time.
The AFC correction signal is available as a DC current at the AFC output (pin 46). A varactor,
connecting to the AFC output and the reference crystal, provides the required tuning action.
See section on AFC for more details.
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相关代理商/技术参数 |
参数描述 |
|---|---|
| WE9104 | 制造商:未知厂家 制造商全称:未知厂家 功能描述:Pulse Telephone Dialer |
| WE9110 | 制造商:未知厂家 制造商全称:未知厂家 功能描述:Pulse Telephone Dialer |
| WE9140 | 制造商:WINBOND 制造商全称:Winbond 功能描述:TONE/PULSE SWITCHABLE DIALER WITH REDIAL |
| WE9140A | 制造商:WINBOND 制造商全称:Winbond 功能描述:TONE/PULSE SWITCHABLE DIALER WITH REDIAL |
| WE9140B | 制造商:WINBOND 制造商全称:Winbond 功能描述:TONE/PULSE SWITCHABLE DIALER WITH REDIAL |
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