The Agilent/Keysight 8657GMSK is a synthesized signal generator engineered for communication testing applications requiring stable, accurate signal generation with integrated GMSK modulation capability. The instrument delivers precise frequency synthesis across a wide operating range with exceptional spectral purity and flexible modulation options for complex waveform generation.
Technical Specifications
Frequency Range & Resolution
• 100 kHz to 1.04 GHz (8657A) or 100 kHz to 2.6 GHz (8657B)
• Underrange capability to 10 kHz with uncalibrated output and modulation
• Frequency resolution: 10 Hz (8657A) or 1 Hz (8657B)
Output Level
• Range: +13 dBm to –143.5 dBm
• 100 kHz to 1 MHz: +10 dBm to –143.5 dBm
• Resolution: 0.1 dBm
• Level accuracy: ±1.0 dB typical (typically ±0.5 dB)
• Level flatness: ±0.5 dB (100 kHz to 2.06 GHz at 0 dBm setting)
Switching Performance
• Frequency switching: <35 ms (30 ms typical at 25 °C)
Modulation Capabilities
• AM and FM with DCFM (dc-coupled FM) for digital squelching
• Pulse modulation (8657B): rise/fall times 70 dB on/off ratios (fc <1030 MHz)
• 0.3 GMSK modulation option (Opt. 022)
• Phase modulation available (Option 003)
Spectral Performance
• SSB phase noise (CW mode, 20 kHz offset): –124 to –136 dBc/Hz depending on frequency band
• Residual FM (300 Hz to 3 kHz post-detection BW): <1 to <6 Hz across frequency bands
– Key Features
• Dual-model architecture supporting 1.04 GHz (8657A) or 2.6 GHz (8657B) maximum frequency
• Integrated GMSK modulation for digital communication protocols
• Excellent phase noise performance across VHF through UHF bands
• Multiple modulation formats within single instrument platform
• Fine resolution frequency tuning to 1 Hz (8657B)
– Typical Applications
Digital communication receiver testing, modulation fidelity verification, transmitter design validation, and GMSK signal generation for GSM and similar standards-based systems.
