How do I select an oscilloscope for characterizing high speed RF waveforms?

How do I select an oscilloscope for characterizing high speed RF waveforms? An oscilloscope for RF waveform characterization must have sufficient analog bandwidth, sample rate, and dynamic range to accurately capture the signal in the time domain: (1) Analog bandwidth: the oscilloscope bandwidth must exceed the highest frequency component of the signal. Rule of thumb: bandwidth ≥ 5× the fundamental frequency for clean waveform capture. For a 5 GHz RF signal: bandwidth ≥ 25 GHz (to capture harmonics and rise times). For pulsed radar at 10 GHz: bandwidth ≥ 20-30 GHz. For 5G NR FR1 modulated signals (3.5 GHz carrier): bandwidth ≥ 8-12 GHz. For digital signals with fast edges (SerDes, clock): bandwidth = 0.35 / rise_time. A 10 ps rise time requires ≥ 35 GHz bandwidth. (2) Sample rate: must satisfy Nyquist (≥ 2× bandwidth), but practical requirements are higher. For oscilloscopes: sample rate ≥ 2.5× the analog bandwidth. A 25 GHz scope should have ≥ 62.5 GSa/s (gigasamples per second). For single-shot capture (non-repetitive events): the full sample rate is needed on all channels. For equivalent-time sampling (repetitive signals): the effective sample rate can be much higher (100+ GSa/s) using sequential sampling across many trigger events. (3) Dynamic range and vertical resolution: traditional oscilloscopes: 8-bit ADC → 48 dB dynamic range. This is sufficient for digital waveforms but marginal for RF measurements (where 60-80 dB dynamic range is desirable). High-resolution oscilloscopes: 10-12 bit ADC → 60-72 dB dynamic range. Better for characterizing low-level artifacts (noise floor, spurs, distortion). Example: Keysight UXR (10-bit), Tektronix 6 Series B MSO (12-bit via high-res mode). (4) RF-specific features: FFT and spectral analysis: view the signal in the frequency domain (like a spectrum analyzer). Useful for identifying spurs, harmonics, and modulation sidebands. Demodulation and EVM: some oscilloscopes include vector signal analysis software (e.g., Keysight 89600 VSA on the oscilloscope). This turns the scope into a wideband VSA for EVM, constellation, and modulation analysis. Time-gated FFT: analyze the spectrum of a signal during a specific time window (useful for pulsed and burst signals). (5) Major instruments: Keysight UXR (Infiniium): 13-110 GHz, 10-bit, 256 GSa/s. The benchmark for high-bandwidth RF and SI measurements. Price: $100,000-800,000. Tektronix DPO70000SX: 70 GHz, 200 GSa/s. Excellent for SerDes and radar. Price: $100,000-500,000. Tektronix 6 Series B: 10 GHz, 12-bit (high-res mode), 50 GSa/s. Great value for sub-10 GHz RF. Price: $15,000-60,000. R&S RTP: 16 GHz, 10-bit, 40 GSa/s. High dynamic range for mixed-signal work. Price: $30,000-100,000.