The Tektronix SD-24 is a dual-channel TDR/sampling head for high-bandwidth signal acquisition, delivering 20 GHz equivalent bandwidth with 17.5 ps or less rise time. Designed for the 11800-series oscilloscope platform, it combines precision sampling with integrated TDR pulse generation to characterize transmission lines, measure differential and common-mode responses, and analyze crosstalk in high-speed circuits.
Technical Specifications
Bandwidth & Timing
• Equivalent bandwidth: 20 GHz
• Acquisition rise time: 17.5 ps or less
• TDR reflected rise time: 35 ps or less
• TDR incident rise time: 28 ps typical (10% to 90%)
• Time coincidence between TDR steps: adjustable to less than 1 ps
TDR Step Parameters
• Amplitude: adjustable to ±250 mV
• Polarity: selectable independently per channel
• Source resistance: 50 ±0.5 Ω
• Internal termination: 50 Ω
Signal Integrity
• Noise: 75 μVRMS typical without smoothing; 35 μV typical with smoothing
• Aberrations at ±250 mV amplitude:
– 10 ns to 20 ps before step: ±3% or less
– Less than 300 ps after step: +10%, −5% or less
– 300 ps to 5 ns after step: ±3% or less
– Elsewhere: ±1% or less
– Key Features
• Dual-channel simultaneous acquisition and independent TDR generation
• Built-in TDR pulse generator with adjustable timing and amplitude
• Selectable differential and common-mode TDR modes
• Precision 3.5 mm SMA connectors (one per channel)
• Integrated 50 Ω termination
• Noise smoothing function for enhanced signal clarity
– Typical Applications
• High-speed transmission line characterization
• TDR/TDT measurements on differential pairs and single-ended signals
• Crosstalk and coupling analysis
• Device and component rise-time evaluation
• Common-mode and differential-mode signal testing
– Compatibility & Integration
The SD-24 integrates directly into Tektronix 11800-series oscilloscopes, CSA803C, and 11801C mainframes via front-panel compartment installation.
