The Agilent/Keysight 11975A is a leveled microwave amplifier that extends the frequency range of spectrum analyzers and sweep oscillators into the microwave band. It operates from 2.0 to 8.0 GHz with adjustable output power between +6 and +16 dBm, featuring automatic level control (ALC) capability and switchable operation modes. The 11975A serves as a local oscillator (LO) driver for harmonic mixers, delivering frequency-dependent gain that ranges from 15 dB at lower frequencies down to 9 dB at upper band edges. Harmonic and non-harmonic distortion remain well-controlled across the output power range, while a dedicated bias current output supplies adjustable current to external harmonic mixers with ±11 mA maximum capability and 10 µA resolution. The unit accepts input power up to +30 dBm (1 watt) and requires only 100–240 VAC at less than 36 VA, making it suitable for bench and system integration applications.
Technical Specifications
Frequency & Output Power
• Operating range: 2.0 to 8.0 GHz
• Output power (adjustable): +6 to +16 dBm
• Gain variation: 15 dB (2.0–4.5 GHz), 11 dB (4.5–6.1 GHz), 9 dB (6.1–8.0 GHz)
Automatic Level Control
• ALC switchable on/off with visual indicator
• Minimum input power for leveled output: >20 dB above noise floor
• Required input power: +2 dBm (2.0–4.5 GHz), +5 dBm (4.5–6.1 GHz), +8 dBm (6.1–8.0 GHz)
Input & Output
• Maximum input power: +30 dBm (1 watt)
• Maximum input voltage: +35 Vdc
• Input SWR (ALC off): Typically 2.7:1
• RF connectors: SMA female, 50 Ω (Option 001: Type N female)
Distortion Performance
• Harmonic distortion (2nd & 3rd): Below fundamental at ≤+16 dBm output
• Non-harmonic distortion: Typically >60 dB below fundamental at ≤+16 dBm output
Bias Current Output
• Maximum output: ±11 mA, typically ±3 Vdc
• Resolution: 10 µA
• Short-circuit protection: Typically ≤10 mA
• Connector: BNC female
Power Requirements
• AC input: 100, 120, 220, or 240 volts ±5%/-10%; 48 to 440 Hz
• Consumption: <36 VA
Physical & Environmental
• Dimensions: 213 mm × 102 mm (8.4 in × 4.0 in)
• Weight: 3.04 kg net (6.8 lbs)
• Operating temperature: 0 to 55 °C
• Storage temperature: -40 to +75 °C
• Compliance: MIL-T-28800C Type III Class 5 Style E; EMI per MIL STD 461A and CISPR 11 (1975)
– Compatibility & Integration
Recommended for use as LO driver with Keysight 11970/74 series harmonic mixers. Note: This product is obsolete; Keysight 87415A is the recommended alternative.
