HP / Agilent 11721A Frequency Doubler

The HP/Agilent 11721A is a passive RF frequency doubler that extends signal generator and synthesizer output capabilities by translating input frequencies to double their original value. Operating across 50 MHz to 1300 MHz at the input, it delivers 100 MHz to 2600 MHz at the output—enabling access to higher frequency bands without replacing instrumentation. The passive 50-ohm design achieves conversion loss below 15 dB (referenced to +13 dBm input, 50–1280 MHz band) while maintaining spurious suppression of –50 dBc or better for harmonic content. Fundamental feed-through (f/2) and tertiary products (3f/2) are held to –15 dB relative to desired output.

– Technical Specifications

• Input Frequency Range: 50 MHz to 1300 MHz
• Output Frequency Range: 100 MHz to 2600 MHz
• Conversion Loss: <15 dB (with +13 dBm input, 50–1280 MHz)
• Spurious Outputs: –50 dBc or better; f/2 and 3f/2 components at –15 dB (referenced to output frequency, +13 dBm input)
• Input SWR: Typically 1.5
• Input/Output Impedance: 50 ohms nominal
• Operating Temperature: 0°C to +55°C
• RF Connectors: Type N male (input), Type N female (output)
• Physical Dimensions: 161 mm × 30 mm × 20.5 mm; 181 g net weight

– Key Features

• Passive design minimizes conversion loss and spurious generation
• Optimal performance above +10 dBm input power
• Low input SWR (1.5 typical) ensures efficient source coupling
• Frequency modulation passed through with output deviation doubled relative to input
• Amplitude modulation acceptable for applications with input depth below 20%, resulting in <3% AM distortion

– Typical Applications

• Extension of signal generator frequency range beyond native instrument capability
• Test and measurement requiring doubled frequency synthesis
• High-frequency RF and microwave subsystem characterization

– Compatibility & Integration

Designed as an accessory for the HP Model 8662A Synthesized Signal Generator. Compatible with any RF source delivering 50 MHz to 1300 MHz output. Service and operation documentation available under part number 11721-90002.