The Tektronix 1L40 is a spectrum analyzer plug-in module for compatible Tektronix 500-series oscilloscopes, delivering comprehensive frequency-domain signal analysis from 1.5 GHz to 40 GHz. This module transforms oscilloscope displays into real-time spectrum analyzers, enabling rapid identification of signal components, distortion characterization, and modulation analysis across four distinct frequency bands. The 1L40 employs a removable mixer architecture—a coaxial input for 1.5 GHz to 12.4 GHz operation plus three interchangeable external waveguide mixers extending coverage to 40 GHz. Its 1.7 GHz to 4.2 GHz first local oscillator uses a Y1641 SHF triode with resonant cavity circuits and integrated varactor tuning for voltage-controlled frequency capability.
Technical Specifications
• Frequency Coverage: 1.5 GHz to 40 GHz across four removable mixer configurations
• Dispersion: 1 kHz/division to 10 MHz/division in 1-2-5 steps
• Resolution Bandwidth: ≤1 kHz to ≥100 kHz in 11 selectable steps
• IF Attenuator Range: 0 dB to 51 dB
• Display Dynamic Range: ≥40 dB in LOG mode
• First Intermediate Frequency: 150 MHz to 250 MHz
• Sweep Input Voltage: 100 V or 150 V sawtooth from mainframe (rear-mounted selector for 500-series model adaptation)
– Key Features
• Plug-in form factor integrates directly into 500-series oscilloscope mainframes
• Four-band mixer set: basic coaxial (1.5–12.4 GHz), plus waveguide modules for 12.4–18 GHz, 18–26.5 GHz, and 26.5–40 GHz
• Y1641 SHF triode oscillator with cavity tuning and VFC phase-lock capability
• Unfiltered input allows direct display of signals within the 150–250 MHz IF range
• Inverted frequency axis presentation (lower frequencies right, higher left) due to upper-sideband conversion topology
– Typical Applications
• Signal component identification across microwave frequency bands
• Harmonic and spurious distortion measurement
• Modulation characteristic analysis
• Frequency domain troubleshooting in RF/microwave systems
– Compatibility & Integration
The 1L40 connects to Tektronix 500-series oscilloscopes via direct plug-in insertion. RF input accepts coaxial signals up to 12.4 GHz; external waveguide mixers enable higher bands. Sweep synchronization derives from the mainframe’s sawtooth generator through a front-panel BNC connector.
