方严’s Post

# Knowledge sharing RFSDR/RFIC/RFSoC >>>characterizing by PAPR (Peak-to-Average Power Ratio) PAPR is a key performance indicator to characterize RFSDR (even discrete RF transceiver) for wideband OFDM 4G/5G/ signal, to ensure continuous linearity of the module embedded power amplifier. PAPR is simply a power variation characteristic of RF-transmitted OFDM module. OFDM is a multicarrier modulation technique where the available spectrum is divided into subcarriers, with each subcarrier has its dedicated IQ modulator. And each IQ modulator output power level might vary, even overshoot. Therefore, determining PAPR prevent the transceiver power amplifier from linearity into compression. The 4G/5G OFDM each subcarrier power variation, causing the OFDM waveform look noise-like in frequency domain of OTA-channel power measurements of 4G/5G signal. To protect the RF power amplifier (from non-compression state) and prevent 4G/5G OFDM signal gets distorting >>  1, Measure the PAPR(dB) of the RFSoC/RFSDR module, using CCDF measurement of Signal analyser.  2, Subtract measured value from the module rated TX power (supplied from datasheet). 3, The actual module TX power = Rated TX power minus measured PAPR. From hand-on experience, always configure  the module to actual TX power (Not rated power), to prevent the embedded power amplifier compressing, and subsequently leads to intermodulation product/harmonics/Spurs generating. Orthogonal Frequency Division Multiplexing (OFDM) is a type of digital modulation but different from other digital modulation. It must be well understood before being worked on RF-OFDM supported device. Its main setback is its PAPR characteristic behave. As illustrated in the image below, a typical OFDM waveform of 4G signal in in-band channel power measurement mode ( Power VS frequency), it looks noise-like, because of composition of numbers of subcarriers with varying power level. Additionally, as shown below, there might be in-band interference, but  difficult to detect with normal spectrum analyser. While the analyser with REAL-TIME spectrum analysis feature could easily detect the interference. #4G #5G #NR #LTE #LTE-A #RF #NTN #MICROWAVE

The IQ, image reject, and single sideband mixers have a significant impact on the dynamic range and spurious suppression. These mixers play a crucial role in achieving high performance while minimizing size and cost. The dynamic range of the system is limited by isolation, spurious suppression, LO feedthrough, and other factors. The 2IF x 1 LO spur and LO feedthrough can limit the dynamic range, even if the sideband is adequately suppressed. The bleedthrough of the LO signal is frequently higher in power than the suppressed sideband in a single sideband upconversion scheme, which may not reduce filter requirements without excellent LO-RF isolation. Furthermore, the implementation of IQ/IR/SSB mixers depends on system goals, performance, bandwidth, dynamic range, and cost. The mixers can be realized for low cost in a small package using digital signal processing or analog CMOS circuits, but this may come at the cost of lower operation frequency, narrower bandwidth, lower linearity, and higher development costs. For broadband, high dynamic range microwave frequency applications, the standard approach uses passive diode mixers. In the context of a practical X-band synthesizer application, the mixers’ linearity is improved in two ways: signal splitting reduces the signal power seen by each mixer, improving overall power compression, two-tone intermodulation, and higher order multitone intermodulation distortion. Additionally, by dividing signals in quadrature and combining them in phase, some isolations and spurious signals either add in quadrature phase or out of phase, leading to improvements in LO-RF isolation and spur suppression. #telecommunications #radarsystems #signalprocessing #broadband #frequency #cmos #rfmixer #radiofrequency #5gnetwork #narrowband #ultrawideband #maxwellequations

Transforming Communication: The Unstoppable Force of Software-Defined Radio (SDR) 🌟   Software-Defined Radio (SDR) is causing a seismic shift in wireless communication, swapping out traditional hardware components with software and delivering unrivaled flexibility and performance. 🔥   What Is SDR?   SDR employs software to carry out tasks that were previously the domain of hardware, like mixing, filtering, and modulating signals. This brings:   - Flexibility: It can be effortlessly reconfigured to back various standards and waveforms. 👍 - Performance: It boosts signal processing capabilities. 👏   How SDR Works   The components include:   1. Antenna: Grabs radio signals. 📡 2. RF Tuner: Filters and picks the desired frequencies. 🔊 3. ADC: Converts analog signals to digital. 📱 4. DDC: Handles the processing of digital signals. 💻 5. DSP: Decodes and demodulates the signals. 📊 6. Computer: Runs the controlling software. 🖥️   Applications of SDR   1. Radio Astronomy:    - Tracks celestial signals by adjusting frequencies. 🌌 2. Military:    - Detects and jams enemy signals and ensures secure communication. 🛡️ 3. Emergency Services:    - Maintains communication during disasters. 🚨 4. Commercial Wireless Networks:    - Monitors the spectrum and detects interference. 🌐 5. Amateur Radio:    - Facilitates long-distance communication and signal decoding. 📻   Why SDR Is a Game-Changer   1. Flexibility: Reconfigurable for a multitude of tasks. 🤝 2. Upgradability: New features can be added through software updates. 🆙 3. Cost-Effective: Replaces multiple specialized devices. 💰   Real-World Impact   - Cellular Networks: Integrates new standards like 5G. 5G 📶 - Military Operations: Adapts quickly to counter threats. 🪖 - Emergency Response: Ensures strong communication channels. 🆘   Discover how SDR can supercharge your communication systems at www.DynamicEngineers.com. #TechInnovation #SDR #WirelessCommunication #ModernTech #ElectronicsEngineering #CommunicationRevolution #SDRImpact #FrequencyControl #MicrowaveJournal #MicrowaveJournalCN #DynamicEngineers #EverythingRF #RadioCommunication #5GandSDR

In the current issue of the Journal of Lightwave Technology, Infinera authors detail DSP design mechanisms to process digital subcarriers and DSP algorithm requirements to accommodate low per-subcarrier symbol rates and operation on intermediate digital carriers. Read it now: #OpticalNetworking #DSP #PointToMultipoint

In the current issue of the Journal of Lightwave Technology, Infinera authors detail DSP design mechanisms to process digital subcarriers and DSP algorithm requirements to accommodate low per-subcarrier symbol rates and operation on intermediate digital carriers. Read it now: #OpticalNetworking #DSP #PointToMultipoint

practical example on how powerful is the Optical WDM integration boards - in this example we have OH20 - OH20 is an intelligent system integrated in single WDM board - OH means optical hybrid ,, 20 means it can route optical Traffic from/ to 20 direction - the OH20 board contain the below : 1- ROADM 2- EDFA amplifier 3- OSC board 4- XFIU 5- VOA 1- ROADM is responsible for flexibily add , drop any wavelength from/ to any direction up to 20 direction , DWSS integrated 2- amplifier responsible for amplifying the optical signal to extend the distance with IP to 31 db gain 3- OSC board responsible for processing the optical supervisory signal for nodes mangment 4- XFIU is responsible for multiplexing and demultiplexing the OSC mangment signal with main traffic signal 5- VOA is variable optical attenuator responsible for optical power control and adjustment - This board needs 2 slots in the cabinet - this board is Huawei board and can be integrated in Huawei OSN 9800 M series sub rack - Nokia and other vendor also has the same concept of functions integration in to single smart board - it can support ASON technology , power locking , gain locking , internal signal analysis - it support C band , extended C band , super C band from 190.5 Thz - 196.6 Thz #OSN #DWDM #OTN #Optical #m_saeed

WDM: How to integrate the boards power?

In the current issue of the Journal of Lightwave Technology, Infinera authors detail DSP design mechanisms to process digital subcarriers and DSP algorithm requirements to accommodate low per-subcarrier symbol rates and operation on intermediate digital carriers. Read it now: #OpticalNetworking #DSP #PointToMultipoint

In the current issue of the Journal of Lightwave Technology, Infinera authors detail DSP design mechanisms to process digital subcarriers and DSP algorithm requirements to accommodate low per-subcarrier symbol rates and operation on intermediate digital carriers. Read it now: #OpticalNetworking #DSP #PointToMultipoint