The Agilent/Keysight 8657D is a specialized Pi/4 DQPSK signal generator engineered for NADC and PDC wireless system validation. It extends the 8657 series with digital modulation capability essential for testing North American Digital Cellular and Japanese Personal Digital Cellular mobile devices across R&D, manufacturing, and field support environments.
Technical Specifications
Frequency Performance
• Frequency range: 100 kHz to 1.03 GHz (analog)
• Frequency resolution: 1 Hz
• Underrange capability: 10 kHz with uncalibrated output and modulation
• Switching speed: +16 dBm at most frequencies
• Absolute level accuracy: ±1.5 dB (>+7 dBm); ±1.0 dB (+7 dBm to –127 dBm); ±1.5 dB (<–127 dBm)
• Level flatness: ±0.5 dB (100 kHz to 2.06 GHz at 0 dBm setting)
• Reverse power protection: 50 W
• Output impedance: 50 Ω nominal
Modulation Specifications
• Standard modulation: AM, FM, Pulse Modulation
• Pi/4 DQPSK for NADC/PDC digital applications
• Error Vector Magnitude (EVM): <3.2%
• DC-coupled FM: Eliminates droop on low-rate tones or digital data
• Pulse modulation (8657B): Rise/fall times 70 dB on/off ratios
Spectral Purity
• Low residual FM: <4 Hz at frequencies <1040 MHz (8657B)
• Low single-sideband phase noise for adjacent channel selectivity testing
• Low RF leakage minimizes measurement interference
– Key Features
• Calibrated output from 100 kHz to 1.03 GHz with 1 Hz resolution
• Standing Wave Ratio <1.5 (levels ≤–6.5 dBm); <2.0 (levels ≤+13 dBm) on 8657B
• Pi/4 DQPSK capability optimized for NADC and PDC standards
• Exceptional frequency stability with minimal retuning drift
– Typical Applications
• NADC and PDC mobile device receiver/transmitter validation
• Manufacturing test for digital cellular handsets
• Field support and troubleshooting of wireless systems
• Adjacent channel selectivity and modulation accuracy testing
– Compatibility & Integration
The 8657D builds on the proven 8657 platform, providing backward compatibility while adding specialized digital modulation for cellular standards.
