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Model 845 Microwave Signal Generator (9 kHz to 26.5 GHz)

Versatile single-channel microwave and RF source covering 9 kHz to 26.5 GHz with ultra-low phase noise, fast switching, and broad VLF-through-K-band coverage.

Specifications reproduced from Model 845 datasheet V2.76 (dc-81405202). Warranted at 23 ±5 °C after 30-minute warm-up unless stated.
Berkeley Nucleonics Model 845 microwave and RF signal generator

1Introduction

Very compact, portable analog signal generator models with a range from 9 kHz (with option 9K) up to 26.5 GHz. The Model 845 is a series of low-noise and fast-switching microwave signal generators covering continuous frequency ranges from as low as 100 kHz up to 12, 20, and 26 GHz, respectively, with a 0.001 Hz resolution.

The Model 845 provides an accurately leveled output power range and high spurious suppression. Advanced frequency synthesis with fractional-N divider makes for low SSB phase noise and micro-Hz resolution.

The standard Model 845 includes amplitude modulation (AM), DC-coupled low-distortion wideband frequency modulation (FM), PM, FSK and PSK, frequency chirp, and fast pulse modulation with internal pulse train generator. Three internal modulation sources are available. All modulation modes of the Model 845 can be combined. This allows the generation of complex modulation signals for modern communication and location systems. The combination of pulse modulation and FM simulates Doppler effects or chirp signals. Simultaneous AM and pulse modulation provide the types of signal occurring in pulse radar applications with rotating antenna. The combination of FM and AM can be used to check fading effects of FM receivers.

All Model 845 units allow fast analog and digital sweeps including flexible list sweeps, where frequency, power, and dwell times can be set individually. A flexible triggering capability simplifies synchronization within test environments.

All Model 845 units operate with an ultra-stable temperature-compensated 100 MHz reference (OCXO) to ensure minimal drift, and can be phase-locked to any stable external reference in a range from 1 to 250 MHz. Additionally, optimum phase-synchronous signals can be achieved by bypassing the internal reference and feeding a 100 MHz signal directly as reference. The 845 supports various standard interfaces such as USB-TMC, LAN, and GPIB.

Definitions

The specifications in the following pages describe the warranted performance of the instrument for 23 ±5 °C after a 30-minute warm-up period, unless otherwise stated.

  • Min/Max: Parameter range that is guaranteed by product design, and/or production tested. Warranted performance specifications include guard-bands to account for the expected statistical performance distribution, measurement uncertainties, and changes in performance due to environmental conditions.
  • Typical: Expected mean values, not warranted performance.

Applications

  • R&D low-noise microwave source
  • Production testing (industry-leading switching times, high dynamic range)
  • Service and maintenance (battery operation)
  • Signal simulation (Radar, WiMax, UWB)
  • Aerospace & defense (pulse modulator, chirps)

2Available Options

OptionDescription
HPDelivers higher maximum output power, to a level up to +27 dBm.
PE2Optional power level extension to accurately level below -120 dBm.
FSSubstantially enhances the switching speed.
9KLow-frequency extension down to 9 kHz (845-20, 845-12 only).
1URMModifies the form factor to a 19" rack-mountable 1HU enclosure.
FILTHarmonic filtering.

3Frequency Parameters & Range

ParameterMinTypicalMaxNote
Frequency range
845-12100 kHz12.0 GHz
845-20100 kHz20.0 GHzSettable to 20.5 GHz
845-26100 kHz26.0 GHzSettable to 30 GHz
Option 9 kHz9 kHzLow-frequency extension
Resolution0.001 Hz
Phase resolution0.1 deg
Frequency / amplitude setting time
Standard200 µs300 µs
Option FS30 µs
Option NEC30 µsFstep < 2.2 GHz

4Level Performance

Output power. Check the maximum output power plots below. Level resolution is 0.01 dB.

Figure 1: Typical Maximum Output Power from 9 kHz to 1 MHz (option 9K)
Figure 1: Typical Maximum Output Power from 9 kHz to 1 MHz (option 9K).
Figure 2: Maximum Output Power 845-26, HP with and without option PE2
Figure 2: Maximum Output Power 845-26, HP with and without option PE2.
Configuration / frequency rangeMinMax
Standard
9 kHz to 100 kHz (option 9K)-20 dBm+15 dBm
100 kHz to 26 GHz-20 dBm+15 dBm
Option PE
9 kHz to 100 kHz (option 9K)-90 dBm+13 dBm
100 kHz to 26 GHz-90 dBm+13 dBm
Option PE2
9 kHz to 100 kHz (option 9K)-120 dBm+13 dBm
100 kHz to 26 GHz-120 dBm+13 dBm
Option HP
9 kHz to 100 kHz (option 9K)-20 dBm+15 dBm
100 kHz to 10 MHz-20 dBm+20 dBm
0.01 to 12 GHz-20 dBm+21 dBm
12 to 20 GHz-20 dBm+20 dBm
20 to 24 GHz-20 dBm+19 dBm
24 to 26 GHz-20 dBm+15 dBm
Option HP and FILT
9 kHz to 100 kHz (option 9K)-20 dBm+15 dBm
100 kHz to 10 MHz-20 dBm+19 dBm
0.01 to 12 GHz-20 dBm+20 dBm
12 to 20 GHz-20 dBm+19 dBm
20 to 24 GHz-20 dBm+18 dBm
24 to 26 GHz-20 dBm+14 dBm
Option HP and PE2
9 kHz to 100 kHz (option 9K)-120 dBm+13 dBm
100 kHz to 10 MHz-120 dBm+20 dBm
0.01 to 12 GHz-120 dBm+21 dBm
12 to 20 GHz-120 dBm+19 dBm
20 to 24 GHz-120 dBm+18 dBm
24 to 26 GHz-120 dBm+14 dBm
Options HP and PE2 + FILT
9 kHz to 100 kHz (option 9K)-120 dBm+13 dBm
100 kHz to 10 MHz-120 dBm+19 dBm
0.01 to 12 GHz-120 dBm+20 dBm
12 to 20 GHz-120 dBm+18 dBm
20 to 24 GHz-120 dBm+17 dBm
24 to 26 GHz-120 dBm+13 dBm
Options HP and PE
9 kHz to 100 kHz (option 9K)-90 dBm+13 dBm
100 kHz to 10 MHz-90 dBm+20 dBm
0.01 to 12 GHz-90 dBm+21 dBm
12 to 20 GHz-90 dBm+19 dBm
20 to 24 GHz-90 dBm+18 dBm
24 to 26 GHz-90 dBm+14 dBm
Option HP and PE + FILT
9 kHz to 100 kHz (option 9K)-90 dBm+13 dBm
100 kHz to 10 MHz-90 dBm+19 dBm
0.01 to 12 GHz-90 dBm+20 dBm
12 to 20 GHz-90 dBm+18 dBm
20 to 24 GHz-90 dBm+17 dBm
24 to 26 GHz-90 dBm+13 dBm

5Power Uncertainty & VSWR

Reverse Power Protection and VSWR

Figure 3: Typical VSWR (845-20)
Figure 3: Typical VSWR (845-20).
ParameterMinTypicalMaxNote
Reverse power protection — DC voltage±15 V
Reverse power protection — RF power+30 dBm
Output impedance50 Ω
VSWR
< 20 GHz1.5
> 20 GHz2.0

Power Level Uncertainty (ALC on, Model 845 + PE2/PE)

Values are the warranted figure, with the typical value in parentheses.

Figure 4: Typical Frequency Response 0 to 20 GHz at -20, 0, and +20 dBm
Figure 4: Typical Frequency Response 0 to 20 GHz at -20, 0, and +20 dBm (level error versus frequency).
Figure 5: Typical Frequency Response 0 to 20 GHz (level error vs. power set)
Figure 5: Typical Frequency Response 0 to 20 GHz at -20, 0, and +20 (level error versus power set).
Frequency>15 dBm to Pmax-15 to +15 dBm-70 to -15 dBm< -70 dBm
10 MHz to 10 GHz1.6 dB (0.8 dB)1.0 dB (0.3 dB)1.5 dB (0.4 dB)1.8 dB (0.5 dB)
100 Hz to fmax1.6 dB (0.8 dB)1.0 dB (0.3 dB)1.5 dB (0.4 dB)2.0 dB (0.5 dB)

User flatness correction: up to 2000 points. Temperature effects: 0.015 dB/°C (typical) in the range 0 to 45 °C.

6Phase Noise

Figure 6: Phase Noise Performance (1 Hz to 100 MHz offset) at different frequencies
Figure 6: Phase Noise Performance (1 Hz to 100 MHz offset) at different carrier frequencies.
SSB phase noise (standard)TypicalMax
1 GHz, 10 Hz offset-80 dBc/Hz-77 dBc/Hz
1 GHz, 20 kHz offset-130 dBc/Hz-128 dBc/Hz
1 GHz, 100 kHz offset-131 dBc/Hz-129 dBc/Hz
4 GHz, 10 Hz offset-68 dBc/Hz-65 dBc/Hz
4 GHz, 20 kHz offset-118 dBc/Hz-116 dBc/Hz
4 GHz, 100 kHz offset-119 dBc/Hz-117 dBc/Hz
20 GHz, 10 Hz offset-51 dBc/Hz-48 dBc/Hz
20 GHz, 20 kHz offset-104 dBc/Hz-102 dBc/Hz
20 GHz, 100 kHz offset-104 dBc/Hz-100 dBc/Hz
Wideband noise-150 dBc/Hz
Amplitude noise at 10 GHz-130 dBc/Hz (-140 dBm)

7Spectral Purity

Spectral purity at +5 dBm.

Figure 7: Harmonics, Standard
Figure 7: Harmonics, standard.
Figure 8: Harmonics, 845-12 with option FILT
Figure 8: Harmonics, 845-12 with option FILT.
ParameterTypicalMaxNote
Output harmonics-40 dBc-30 dBcSee plot
845-12 with option FILT, 10 MHz to 8 GHz-40 dBc-30 dBcSee plot
845-12 with option FILT, 8 GHz to 12 GHz-60 dBc-50 dBc
845-20 with option FILT, 10 MHz to 12 GHz-40 dBc-30 dBcSee plot
845-20 with option FILT, 12 GHz to 20 GHz-65 dBc-50 dBc
845-26 with option FILT, 10 MHz to 15 GHz-40 dBc-30 dBcSee plot
845-26 with option FILT, 15 GHz to 20 GHz-60 dBc-50 dBc
Sub-harmonics
< 20 GHz-75 dBc-65 dBc
> 20 GHz-50 dBc-40 dBc
Non-harmonic spuriousCW +10 dBm, > 3 kHz offset
< 312 MHz-80 dBc-66 dBc
> 312 to 625 MHz-75 dBc-70 dBc
> 625 MHz to 1.5 GHz-75 dBc-65 dBc
> 1.5 GHz to 2.5 GHz-70 dBc-65 dBc
> 2.5 GHz to 5 GHz-65 dBc-60 dBc
> 5 GHz to 10 GHz-60 dBc-55 dBc
> 10 GHz to 20 GHz-55 dBc-50 dBc
> 20 GHz-50 dBc-45 dBc
Residual FM @ 10 GHz15 Hz0.3 kHz to 3 kHz, weighted (ITU-T), RMS
Residual AM @ 10 GHz0.02%RMS value (0.01 kHz to 15 kHz)
Figure 9: Harmonics, 845-20 with option FILT
Figure 9: Harmonics, 845-20 with option FILT.
Figure 10: 845-26 with option FILT
Figure 10: Harmonics, 845-26 with option FILT.

8Sweeping & Switching

Digital power / frequency / list sweeps. Sweep type: linear, logarithmic, random. Sweeps can be performed with combined internal or external AM/FM/PM/pulse modulation running; with modulation enabled, the minimum step time increases to 2 ms.

Sweep timing: TRIG IN, TRIG OUT (signal valid), and RF valid showing tstep, tde, tinv, and tval
Sweep timing relationship between TRIG IN, TRIG OUT (signal valid), and RF valid, showing tstep, tde, tinv, and tval.
Figure 15: Typical switching transient from 12 GHz to 14 GHz step
Figure 15: Typical switching transient from 12 GHz to 14 GHz step.
ParameterMinTypicalMaxNote
Step time (tstep)
Standard400 µs19998 s
Option FS40 µs
Dwell time (tval)10 µs9999 s
Off-time incl. transient time (toff)09999 s
Transient time (ttnv)
Standard270 µs
Option FS30 µs
Timing delay (tde)
Standard2 to 10 µs
Option FS50 ns
Time resolution
Standard0.1 µs
Option FS5 ns
Timing accuracy per point
Standard3 µs
Option FS5 ns

9Reference Frequency

REF IN input and REF OUT output are at the rear panel.

ParameterMinTypicalMaxNote
Internal reference frequency100 MHz
Initial accuracy±40 ppbCalibrated at 23 ±3 °C at time of calibration, user adjustable
Temperature stability (0 to 50 °C)±100 ppb
Aging, 1st year0.5 ppm
Aging per day (after 30 days operation)5 ppb
Warm-up time5 min
Output of internal reference10 / 100 MHz
Output power0 dBm
Output impedance50 Ω
Bypass internal reference input100 MHz, -5 to +10 dBmHigh phase-synchronous mode
External input range (phase lock)1 MHz250 MHzUser programmable
Reference input level-5 dBm0 dBm+13 dBm
Lock range±1.5 ppm
Reference input impedance50 Ω

10Outputs & Triggers

Multi-Purpose Output (FUNC OUT)

Output is FUNC OUT at the rear panel.

Multifunction generatorMinTypicalMaxNote
Frequency range (sine, triangle, square)
Sine10 Hz3 MHz
Triangle10 Hz1 MHz
Square50 kHz
Frequency resolution0.1 Hz
Output voltage amplitude (peak-peak)
Sine, triangle10 mV2 V
Square (CMOS output)5 V
Harmonic distortion1%< 100 kHz, 1 Vpp
Output impedance50 Ω / CMOSSine, triangle / square wave
Video output (of internal pulse modulator)MinTypicalMax
OutputCMOS
Period30 ns50 s
Pulse width15 ns50 s
RF delay10 ns

TRIG OUT synchronization modes for multiple sources: trigger on sweep start, trigger on each point, signal valid (option FS).

Trigger (TRIG IN)

Input is TRIG IN at the rear panel. Trigger Output (TRIG OUT) follows the Multi-Purpose Output (FUNC OUT) above. See the sweep timing diagram in the Sweeping & Switching section.

ParameterMinTypicalMaxNote
Trigger typesContinuous, single, gated, gated direction
Trigger sourceRF key, external, bus (GPIB, LAN, USB)
Trigger modesContinuous free run, trigger and run, reset and run
Trigger latency
Standard2 µs
Option FS130 ns
Trigger uncertainty
Standard5 µs
Option FS10 ns
External trigger delay
Standard (programmable)50 µs40 s
Option FS50 ns10 s
External delay resolution
Standard15 ns
Option FS10 ns
Trigger modulo1255Execute only on Nth trigger event
Trigger polarityRising, falling
External trigger input threshold0.85 V0.9 V0.95 VTTL compatible
External trigger input voltage range-0.5 V+5.5 VTTL compatible
External trigger input hysteresis60 mV

11Modulation

Combinations of AM/PM/FM/pulse are possible. See the user manual for more details.

Pulse Modulation

ParameterMinTypicalMaxNote
On/off ratio75 dB (typical)At +10 dBm
Repetition frequencyDC10 MHz
Pulse width
ALC hold100 ns5 s
ALC hold, options NP or FS30 ns5 s
ALC on500 ns
Pulse rise/fall time
< 5 GHz30 ns
> 5 GHz5 ns
Duty cycle0.05%99.95%
Pulse resolution30 ns
PolaritySelectable
External input threshold0.85 V0.9 V0.95 VTTL compatible
External input voltage range-0.5 V+5.5 VTTL compatible
External input hysteresis60 mV
Delay (to RF)20 ns40 ns

Pulse Pattern Modulation

Using internal pattern generator.

ParameterMinTypicalMaxNote
Pulse bit width
ALC hold100 ns
ALC hold, or FS ALC on30 ns
ALC on500 ns
Programmable pattern length24096
Duty cycle0.05%99.95%
Pulse bit resolution
Standard30 ns
Option FS5 ns
PolaritySelectable

N-Pulse Modulation (Option FS)

N-pulse modulation timing: P1 to P4 widths, delays, off times, and period
N-pulse modulation timing parameters: P1 to P4 widths, delays, off times, and period.
ParameterMinTypicalMaxNote
Period30 ns21 s
N-Pulse type1 to 4No overlapping with other pulses
N-Pulse width (P1, P2, P3, P4 widths, individually settable)
ALC hold30 ns21 s
ALC on500 ns21 s
N-Pulse delay (P1 delay)0 ns21 s
N-Pulse delay (P2, P3, P4)Min: end of prior pulse + min off time
N-Pulse width and delay resolution5 ns
N-Pulse off time1 µs21 sDetermined by pulse delay and prior pulse width

Frequency Modulation

ParameterMinTypicalMaxNote
Maximum frequency deviation (peak)00.05·f< 0.5 GHz
Maximum frequency deviation (peak)0N·200 MHz0.5 GHz to 2.5 GHz (N=0.125); 2.5 GHz to 5 GHz (N=0.25); 5 GHz to 10 GHz (N=0.5); > 10 GHz to 20 GHz (N=1)
Deviation accuracy, < 100 kHz rate0.5%2%
Deviation accuracy, > 100 kHz rate2%5%
Distortion< 1%1 kHz rate, 50 kHz deviation
Modulation rateDC100 kHz> -3 dB frequency response
Modulation waveformsSine, triangle, FSK
External input sensitivity (AC coupled)0 to N·200 MHz / VAdjustable for ±1 V range
External input sensitivity (DC coupled)0 to N·100 MHz / VDiscrete values, ±5 V range
Total harmonic distortion< 1%1 kHz rate & N·1 MHz deviation

Frequency Chirps (linear ramp, up/down)

ParameterMinMaxNote
Span10%Of carrier frequency
Chirp time (tchirp)10 ns60 s
Total duration of finite repeated chirps (tchirp · repetitions)
Standard64.1 s
With option FS21.4 s
Slope100 MHz/µs
Number of frequencies65,000

Phase Modulation

ParameterMinTypicalMaxNote
Phase deviation (peak)0N·300 rad
Modulation rateDC100 kHz> -3 dB frequency response; max. phase deviation degrades above 20 kHz modulation rate
Modulation waveformsSine, triangle, FSK
External input sensitivitySettable 0.1 rad/V to 360 rad/V
Total harmonic distortion< 1%1 kHz rate & N·100 rad deviation

Amplitude Modulation

ParameterMinTypicalMaxNote
Modulation rate0.1 Hz50 kHz
Modulation waveformsSine, triangle, square
Modulation depth0%100%Settable
Accuracy (f ≥ 10 MHz)0.8%1.4%f-carrier, modulation depth < 80% & 1 kHz modulation rate, power 0 dBm
Distortion (f ≥ 10 MHz)1%2%
External input range0 V5 VTo GND

12Connectors

Front Panel (Touch Screen Version)

Model 845 front panel: rotary knob/button and RF 50 ohm connector
Front panel (touch screen version): rotary knob/button (1) and RF 50 Ω connector (2).
  1. Rotary knob / button: The rotary button is used to change the value selected on the screen.
  2. RF 50 Ω connector: This female N-type or SMA connector provides the output for generator signals. The impedance is 50 Ω. The reverse power damage level is +30 dBm maximum. The maximum allowed DC level is ±10 V. Please check the data sheets for more details.

Rear Panel

Model 845 rear panel connectors and controls, numbered 1 to 14
Rear panel connectors and controls (numbered 1 to 14).
  1. ΦM: This BNC female connector is the input for FM and PM.
  2. REF IN: This BNC female connector is the input for the reference signal.
  3. TRIG IN: This BNC female connector is the trigger input.
  4. USB B: The USB B connector is used to connect the device to a computer.
  5. LAN: The LAN connector is used to connect the device to a network.
  6. Battery LED: In case the device has a rechargeable battery, this LED indicates whether the battery is charged or not.
  7. Fan holes: The air intake of the fan.
  8. Power supply: Connect the BNC power adaptor to this connector to supply the device with energy.
  9. ON/OFF switch: Turns the device on or off.
  10. Ground screw.
  11. FUNC OUT: This BNC female connector is the output for the function signal.
  12. REF OUT: This BNC female connector is the output for the reference signal.
  13. AM PULSE: This BNC female connector is the input for the AM and the PULSE modulation signal.
  14. Fan holes: The holes by which the air is extruded.

13Ordering Information

Host modelProduct / optionDescription
845-12845-1212 GHz microwave signal generator
845-20845-2020 GHz microwave signal generator
845-26845-2626 GHz microwave signal generator
845-12/20Option 9KFrequency range extension to 9 kHz
845-26Option PEMechanical step attenuator (26 GHz version) down to -90 dBm
845-XXOption PE2Mechanical step attenuator to -120 dBm
845-XXOption HPHigher output power
845-12/20/26Option FILTImproved harmonic filtering
845-XXOption FSUltra-fast switching speed (export control)
845-XXOption FLASHMicroSD card slot for removable SD memory
845-XXOption IECIEC 17025 calibration with certificate
845-XXOption BagPortable bag
845-XXOption GP08 / GPIBGPIB interface.
GPIB interface connector
GPIB interface connector.
845-XXOption EB6External power bank adapter cable with voltage converter for 12 to 25 V supply. Required input connector: inner / outer diameter 2.1 / 5.5 mm.
Model 845 with external power bank adapter cable (Option EB6)
Model 845 powered from an external battery pack via the Option EB6 adapter cable.
845-XXOption 1URM19" 1U rack-mount module. Dimensions 1.7 in H x 16.8 in W x 18.1 in L [42 mm H x 426 mm W x 460 mm L].
19-inch 1U rack-mount module (Option 1URM)
19" 1U rack-mount module (Option 1URM).
845-XXOption RM19" 3U rack-mount kit
845-XXOption REARMove output to rear panel
845-20/26Option OEMOEM package
845-XXOption RetrofitApplies when options are added after first delivery
  1. The options PE3 / GPIB cannot coexist in the standard desktop housing. Please choose a maximum of two of them. No restriction with option 1URM.
  2. When PE or PE2 is chosen, GPIB can no longer be selected.
  3. The options REAR and GPIB cannot be ordered together.

For a configured quote, contact Berkeley Nucleonics Corporation · info@berkeleynucleonics.com · 415-453-9955.

14General Characteristics

CE mark EMC complies with the EMC regulations and directives for emission and immunity to interference (EN 61326-1 Industrial, EN/IEC 61326-2-1). Safety complies with the applicable safety regulation in line with IEC/EN 61010-1.
CharacteristicSpecification
Remote programming interfacesEthernet 100BaseT LAN interface; USB 2.0 host & device; GPIB (IEEE-488.2, 1987) with listen and talk (optional)
Control languageSCPI version 1999.0
Power requirements6.25 ±0.2 VDC; 20 W maximum
Main adapter supplied100–240 VAC in / 6 V, 6.0 A DC out
EnvironmentalLevels similar to MIL-PRF-28800F Class 3 & 4. Samples type tested to be robust against the environmental stresses of storage, transportation, and end-use (temperature, humidity, shock, vibration, altitude, and power line conditions).
Operating temperature range0 to 45 °C
Storage temperature range-40 to 70 °C
Max. relative humidity85% up to 45 °C ambient
Operating and storage altitudeUp to 15,000 feet (4600 m)
EMCComplies with EMC regulations and directives for emission and immunity to interference (EN 61326-1 Industrial, EN/IEC 61326-2-1)
SafetyComplies with applicable safety regulation in line with IEC/EN 61010-1
Weight≤ 6 lbs (2.5 kg) net, ≤ 8 lb (4 kg) shipping
Dimensions (H x W x L)4.60 in H x 6.83 in W x 10.30 in L incl. connectors [116.9 mm H x 173.6 mm W x 261.7 mm L]
Recommended calibration cycle24 months