The Keysight (formerly Agilent / HP) 8657B is a high-performance, economical synthesized signal generator offering extended frequency coverage from 100 kHz to 2060 MHz. Designed for stringent receiver testing, it delivers low residual FM and excellent phase noise. The instrument features a wide output power range from +13 to -143.5 dBm with superior level accuracy. It supports simultaneous AM and FM, pulse modulation, carrier phase adjustment for phase-sensitive devices, and an optional 0.3 GMSK modulation capability.

Specifications

Frequency

ParameterValue
Minimum Frequency100 kHz
Maximum Frequency2060 MHz
Frequency Resolution1 Hz

Output

ParameterValue
Maximum Output Power+13 dBm
Output Power Range+13 to -143.5 dBm
Phase Noise<-136 dBc/Hz (at 500 MHz carrier, 20 kHz offset)

Modulation

ParameterValue
Modulation CapabilitiesAM, FM, Pulse
Mixed ModulationSimultaneous combinations of AM and FM
Pulse Modulation Rise/Fall Time< 35 ns
AM Depth Range0 to 99%
AM Resolution1%

General

ParameterValue
Reference OscillatorStandard: < 2 ppm/year aging; Option 001 (High Stability): < 5x10^-10/day aging
InterfacesHP-IB (IEEE-488)

Physical

ParameterValue
Power Supply100/120/220/240 Vac, 50-60 Hz (100/120 Vac also 400 Hz); 200 VA max
Dimensions (W×H×D)425 × 133 × 574

Frequency Characteristics

ParameterValue
Frequency Range100 kHz to 2060 MHz
Frequency Switching Speed< 35 ms

Amplitude / Output Characteristics

ParameterValue
Level Accuracy±1.0 dB (typically ±0.5 dB)
Amplitude OffsetSupported

Phase and Pulse Modulation

ParameterValue
Phase Adjust CapabilityCarrier phase adjust (for phase-sensitive devices)

Connectivity and Interfaces

ParameterValue
Remote Programming InterfaceHP-IB

RF Output

ParameterValue
Output Impedance50 Ω
Reverse Power Protection50 W from a 50 Ω source (0.1 to 2060 MHz), 50 Vdc max

Spectral Purity

ParameterValue
Harmonics<-30 dBc
Spurious (Non-Harmonic)<-60 dBc (100 kHz to 1030 MHz); <-54 dBc (1030 to 2060 MHz)
Sub-harmonics (1030 to 2060 MHz)< -40 dBc

Environmental

ParameterValue
Operating Temperature0 °C to +55 °C
Storage Temperature-40 °C to +71 °C

Connectivity

ParameterValue
Output ConnectorType-N (female)

Power

ParameterValue
Power Consumption200 VA maximum

Technology

Synthesized RF Signal Generator

Applications

In-channel and out-of-channel receiver testing, phase-sensitive device characterization