The RF sampling receiver design can simultaneously grab many different signals from the air, sorting out the useful ones and making them clearer for things like phones and Wi-Fi.
The RF sampling receiver functions by directly acquiring signals within the radio frequency (RF) band, offering a streamlined approach to signal capture. In scenarios involving multiple frequency bands, the signals of interest often inhabit relatively narrow bands, yet they are distributed extensively across the spectrum. This distribution can pose challenges in isolating and capturing specific signals amidst the broader frequency range. Nevertheless, the RF sampling receiver’s capability to directly capture signals within the RF band facilitates efficient handling of diverse signal sources across various frequency bands, providing flexibility and versatility in applications ranging from telecommunications to spectrum analysis.
This reference design from Texas Instruments (TI) presents an RF sampling receiver that can capture signals across various frequency bands. In a broad RF sampling setup, the analog-to-digital converter (ADC) sampling rate determines the maximum bandwidth covered. The relevant information resides within their specific frequency ranges for applications involving multiple bands. In contrast, the spectrum outside these bands typically carries no valuable data and may contain unwanted interference requiring filtration.
Highlighted in this design is the ADC32RF80 telecom receiver that comes equipped with two digital down converters (DDC). These DDCs offer decimation values ranging from 8 to 32 and feature a 16-bit numerically controlled oscillator (NCO) for shifting the captured signal to a digital baseband. Leveraging the high sampling rate of the receiver, the device efficiently captures a broad spectrum of RF signals, including those spread across multiple bands and potential interfering signals.
The DDCs independently mix the desired bands to digital basebands. Through decimation, the output data rate is reduced, enabling digital filtering around the desired band. This filtering eliminates interference and enhances the signal-to-noise ratio (SNR) performance. Such capabilities are crucial for high-end telecommunication receivers that demand exceptional dynamic range.
The design is a cornerstone in wireless base station setups, facilitating multi-band or multi-mode reception. Additionally, it plays a pivotal role in multi-carrier GSM receivers, enabling efficient signal processing across multiple carriers. This technology operates as a feedback receiver in digital pre-distortion, enhancing signal quality. Moreover, it proves invaluable in telecommunications receivers, ensuring robust and reliable signal reception. Furthermore, in carrier aggregation setups, it functions adeptly as a receiver, seamlessly managing multiple carriers’ amalgamation.
With a focus on signal fidelity, the design incorporates low noise and high dynamic range capabilities, essential for discerning subtle signals amidst varying environmental conditions. Further enhancing flexibility, the solution offers programmable decimation ranging from 8 to 32, enabling precise control over signal processing parameters. Additionally, including a dual digital down-converter equipped with independent numerically controlled oscillators empowers the system to efficiently extract and manipulate signals with precision and autonomy, amplifying its versatility across diverse applications.
TI has tested this reference design. It comes with a bill of materials (BOM), schematics, etc. You can find additional data about the reference design on the company’s website. To read more about this reference design, click here.
