AD6649EBZ IF diversity receiver
The AD6649 is a mixed-frequency signal intermediate frequency (IF) receiver with a dual-channel 14-bit 250 MSPS ADC, a wideband digital downconverter (DDC), and a bypassable sample rate converter (SRC) designed to provide a solution for low-cost, small-size, wide-bandwidth, multi-function communication applications.
This dual-channel ADC features a multi-stage, differential pipeline architecture with integrated output error correction logic. Each ADC has a wide bandwidth input that supports a variety of user-selectable input ranges. Integrated voltage reference simplifies design. The duty cycle stabilizer can be used to compensate for fluctuations in the ADC clock duty cycle, allowing the converter to maintain excellent performance.
The ADC data output is internally connected directly to the receiver's digital downconverter (DDC). Dual-channel digital receivers offer flexible processing capabilities. Each receive channel has 4 cascading signal processing stages: a 32-bit frequency converter (CNC oscillator, abbreviated as NCO), an optional sample rate converter, a fixed FIR filter, and an fS/4 fixed frequency NCO.
In addition to the receiver DDC, the AD6649 also has additional features that simplify automatic gain control (AGC) of the system receiver. Using the ADC's fast detection output bit, the programmable threshold detector monitors the input signal power. If the input signal level exceeds the programmable threshold, the quick detection indicator becomes high. Because the threshold indicator has a very low latency, users can quickly adjust down the system gain to avoid over-range at the ADC input.
After digital processing, the data can be routed directly to the 14-bit output ports, which operate at the 1.8 V LVDS signal level.
The AD6649 receiver is capable of digitizing a wide midrange spectrum. Each receiver is designed to receive signals from both the main and diversity channels. This IF sampling architecture significantly reduces device cost and complexity compared to traditional analog techniques or less integrated digital methods. In diversity applications, the output data is in real format because the final NCO offsets the output center frequency to fs/4.
Flexible shutdown options can significantly reduce power consumption when needed.
Setup and control programming can be done using a three-wire SPI-compatible serial interface.
The AD6649 is available in a 64-pin LFCSP package and is rated for an industrial temperature range of −40°C to +85°C.
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- 通信
- 分集无线电系统
- 多模式数字接收机(3G)
TD-SCDMA、WiMax、WCDMA
CDMA2000、GSM、EDGE、LTE
- 通用软件无线电
- 宽带数据应用
Product features:
- 集成双通道、14位250 MSPS ADC。
- 集成宽带抽取滤波器和32位复数NCO。
- 快速超量程和阈值检测。
- 取得专利的差分输入在最高至300 MHz的输入频率下仍保持出色的信噪比(SNR)性能。
- SYNC输入可在多个设备之间实现同步。
- 三线式、1.8V SPI端口可用于寄存器编程和寄存器回读。