Agilent 8657A Specifications Sheet

Spectral performance for general-purpose test

Overview

The Agilent Technologies 8657A and 8657B signal gener­ators are designed to test AM, FM, and pulsed receivers
as well as components. With their exceptional analog
modulation, good spectral purity, and superb output
level performance, these signal generators are ideal for
R&D, manufacturing, and support.

In-channel performance

Measurement confidence

The 8657A and B signal generators provide the spectral
purity and modulation versatility needed for RF testing
of communication and navigation equipment.

Low residual FM ensures wide hum and noise test margins

Hum and noise testing requires a signal generator to
have low residual FM to ensure no measurement error.
The residual FM of the 8657A and B provides the test
margins you need for the most demanding hum and
noise tests.

Output level range and accuracy for sensitivity testing

With a dynamic range from +13 to –143.5 dBm, the
8657A and B allow sensitivity measurements to be made
on even the most sensitive receivers. The 8657A and B
couple this with a level accuracy of ±1 dB (typically

0.5 dB) to –127 dBm across the full temperature range of
0 to 55 degrees C, to give you accurate and repeatable
measurements every time.

Low RF leakage eliminates measurement interference

Sensitivity measurements can often be masked by RF
leakage (radiated emissions). With the 8657A and B, RF
leakage is reduced to a level that assures virtually no
measurement interference.

DCFM faithfully reproduces digital signals

For radios with digital squelching, the 8657A and B have
extremely stable dc-coupled FM (dcFM). The dc coupling
of low-rate tones or digital data eliminates droop, and
the exceptional stability and center-frequency accuracy
when in dcFM mode eliminates the need to retune the
signal generator after dcFM is selected.

Pulse modulation with the 8657B

High-performance pulse modulation (available on the
8657B) will give you confidence in your radar or pulsed
carrier measurements. This includes rise/fall times of
<35 ns, rates from dc to 30 MHz, and better than 70 dB
on/off ratios (fc<1030 MHz).

Agilent 8657A/8657B

Signal Generators

Profile

2

Out-of-channel measurements with the 8657A/B

Low single-sideband phase noise for adjacent channel selectivity
testing

A receiver’s ability to reject unwanted signals is meas­ured using out-of-channel tests. With its good spectral
purity, the 8657A and B make it easy to perform
demanding tests such as adjacent channel selectivity
measurements.

Adjacent channel selectivity measures a receiver’s ability
to pick out a desired signal while rejecting a strong sig­nal one channel away. To measure adjacent channel
selectivity the out-of-channel signal generator must have
low single-sideband (SSB) phase noise and nonharmonic
spurious content at channel spacings, otherwise the in­channel signal is masked. The exceptional phase noise
performance of the 8657A and B provides a cost-effective
solution for many out-of-channel tests.

General purpose and component tests

Output power to drive high-level inputs

For applications requiring high output power, the 8657A
and B can overrange beyond the +13 dBm specified out­put level to >+16 dBm for most frequencies.

DCFM for VCO simulation

State-of-the-art dcFM and wide FM bandwidth make the
8657A and B ideal sources for many VCO simulation
applications. For example, the 8657A or B can be used to
replace a receiver’s VCO during design.

Phase adjust to characterize phase-sensitive devices

The 8657A and B give you the ability to adjust the phase
of the output signal in one-degree increments with
respect to a source that is locked to the same reference
timebase. This feature makes it easy to characterize
phase-detector or phase-interferometer receivers during
design or manufacturing.

Manual tests

100 nonvolatile store/recall registers save set-up time

The 8657A and B offer as a standard feature the ability
to store 100 complete instrument states. This feature
decreases set-up time when performing repetitive tests
and reduces operator errors.

Register sequencing provides semi-automation

Stepping through the store/recall registers is easy with
the front-panel sequence keys or the rear-panel remote­sequence connector. These features allow the user to
sequence through the storage registers in any order.

Automated tests

Reliable output attenuators

With production lines requiring ever-faster throughput,
test equipment must be more reliable than ever. Output
level cycling requires electromechanical relays to switch
in and out of different attenuators to produce varying
output levels. The 8657A and B enhance system up-time
by using a very reliable attenuator technology. The
8657A is especially dependable with its electronic atten­uator design. Instead of using mechanical relays for
switching the attenuators, the 8657A uses solid-state
components for setting output levels. The patented
design uses PIN-diode switching elements with 3 million
hours mean time between failure rate. This exceptional
reliability is backed with a 5-year warranty against
attenuator failure.

Ordering information

Please contact your Agilent Technologies Sales and
Service Office for more information or visit our website
at www.agilent.com/find/tmdir

Option Description

001 High-stability timebase
002 Rear-panel connections
003 Pulse modulation ( 8657B only)
1BN Mil std 45662A calibration certification
1BP Mil std 45622A calibration with test data
907 Front handle kit
908 Rack flange kit
909 Rack flange kit w/ front handle
910 Adds operation/calibration manual and two service manuals
915 Adds service manual
W30 3-year return repair service
W32 3-year return calibration service
W34 3-year standards compliant calibration service
W50 5-year return repair service
W52 5-year return calibration service
W54 5-year standards compliant calibration service

3

Technical specifications

Specifications describe the instruments warranted per-

formance and apply after a 30-minute warm-up. All
specifications are valid over the signal generator’s entire
operating/environment range unless otherwise noted.

Supplemental characteristics (indicated by italic type) are
intended to provide information useful in estimating
instrument capability in your application by describing
typical, but not warranted, performance.

Note: The upper frequency range of the 8657A is 1.04 GHz.
Specifications above 1.04 GHz apply only to the 8657B.

Frequency

Range

8657A 100 kHz to 1.04 GHz
8657B 100 kHz to 2.6 GHz
Underrange To 10 kHz with uncalibrated output and

modulation.

Resolution
8657A 10 Hz
8657B 1 Hz
Accuracy and stability Same as timebase
Switching speed

1

<35 ms.2(30 ms typical at 25 °C)

Phase offset Output signal phase is adjustable in

1-degree nominal increments.

Internal reference oscillator

Std. (typ.) High-stability Option 001

Aging rate ±2 ppm/yr 8657A, 1.5 x 10-8parts/day after 10 days

1.0 x 10-9parts/day after 180 days

8657B, 1.0 x 10-9parts/day after 45 days
Temperature
(0 to 55 °C) ±10 ppm 7 x 10

-9

Line voltage 2 x 10-9(+5%, –10%)
Frequency 50 MHz 10 MHz
Timebase reference Available at a level of >0.15 V

rms

into

output (rear panel) 50 Ω (output of 10, 5, or 1 MHz is selec-

table via internal jumper). If external ref-

erence is used, output will be the same

frequency.

External reference input Accepts any 10, 5, or 1 MHz ±0.002%)
(rear panel) Frequency standard at a level

>0.15 Vrms into 50 Ω

Output

Range (dBm)

8657A +13 dBm to –143.5 dBm into 50 Ω,

+10 dBm to –143.5 dBm for frequencies
from 100 kHz to 1 MHz

8657B +13 dBm to –143.5 dBm into 50 Ω,

+10 dBm to –143.5 dBm with pulse

modulation installed at fc<1.03 GHz
Resolution 0.1 dB
Absolute level accuracy

3

8657A <±1.5 dB (>+7 dBm)

<±1.0 dB (+7 to –127 dBm)

<±1.5 dB (<–127 dBm)

8657B <±1.5 dB (>+3.5 dBm)

<±1.0 dB (+3.5 to –127 dBm)

<±1.5 dB (<–127 dBm)

Level flatness

100 kHz to 2.06 GHz ±0.5 dB, output level setting of 0 dBm
Reverse power protection

to maximum output frequency) 50 watts (from a 50 Ω source)

Maximum DC voltage 8657A, 50 V

8657B, 25 V

SWR

8657A (fc(400 kHz) <1.5 for levels <–3.5 dBm

<2.0 for levels ≤ +13 dBm
8657B <1.5 for levels ≤ –6.5 dBm

<2.0 for levels ≤ +13 dBm

Output impedance 50 Ω nominal

1. To be within 100 Hz of carrier frequency.

2. Add 5 ms when switching to fc>1.03 GHz for the 8657B.

3. Absolute level accuracy includes allowances for detector linearity, temperature,

flatness, attenuator accuracy and measurement uncertainty.

4

Spectral purity

SSB phase noise (in CW mode, at 20 kHz offset)

0.1 to 130 MHz <–124 dBc/Hz (<–130 dBc/Hz, typical)
130 to 260 MHz <–136 dBc/Hz (<–140 dBc/Hz, typical)
260 to 520 MHz <–130 dBc/Hz (<–136 dBc/Hz, typical)
520 MHz to 1.04 GHz <–124 dBc/Hz (<–130 dBc/Hz, typical)

1.04 to 2.06 GHz <–118 dBc/Hz (<–123 dBc/Hz, typical)

Typical Agilent 8657A SSB phase noise at 500 MHz

Typical Agilent 8657B SSB phase noise at 500 MHz

Residual FM (CW mode, rms)

Post detection BW
(rms detector)

Frequency range 300 Hz to 3 kHz 50 Hz to 15 kHz

1

0.1 to 130 MHz <4 Hz (typical <2 Hz) <6 Hz (typical <3 Hz)
130 to 260 MHz <1 Hz (typical <0.5 Hz) <1.5 Hz (typical <1 Hz)
260 to 520 MHz <2 Hz (typical <1 Hz) <3 Hz (typical <1 Hz)
520 MHz to 1.04 GHz 8657A, <4 Hz (typical <1 Hz) 8657A, <6 Hz

8657B, <3 Hz (typical <1 Hz) 8657B, <4 Hz (typical

<1.5 Hz)

1.04 to2.06 GHz <6 Hz (typical <2 Hz) <8 Hz (typical <3 Hz)

1. Typical residual FM specifications for the 50 Hz to 15 kHz post detection band-

width apply only to the 8657B.

5

Residual AM (50 Hz to 15 kHz post-detection noise bandwidth, in CW
mode)

<0.04% AM

Harmonics (≤+7 dBm output levels)

1

8657A <–30 dBc
8657B 0.1 to 1.03 GHz <–30 dBc

1.03 to 1.8 GHz <–25 dBc

1.8 to 2.06 GHz <–25 dBc

Subharmonics (≤+7 dBm output levels)

8657A, 8657B 0.1 to 1.03 GHz None
8657B 1.03 to 1.8 GHz <–40 dBc

1.8 to 2.06 GHz <–35 dBc

Nonharmonics (CW mode)

Offset from carrier

Frequency range 5 kHz to 2 MHz >2 MHz

0.1 to 130 MHz 8657A, <–60 dBc <–60 dBc
8657B, <–63 dBc (typical)

130 to 260 MHz 8657A, <–72 dBc <–60 dBc

8657B, <–75 dBc (typical)

260 to 520 MHz 8657A, <–66 dBc <–60 dBc

8657B, <–66 dBc (typical)

520 MHz to 1.04 GHz28657A, <–60 dBc <–60 dBc

8657B, <–63 dBc (typical)

1.03 to 2.06 GHz 8657B, <–57 dBc (typical) <–54 dBc

Frequency modulation

Maximum FM peak deviation

3

Center frequency AC mode (the lesser of) DC mode

0.1 to 130 MHz 4000 x rate (Hz) or DC mode 8657A, 99 kHz
max. deviation 8657B, 200 kHz

130 to 260 MHz 1000 x rate (Hz) or DC mode 8657A, 50 kHz

max. deviation 8657B, 50 kHz

260 to 520 MHz 2000 x rate (Hz) or DC mode 8657A, 99 kHz

max. deviation 8657B, 100 kHz

520 MHz to 1.04 GHz 4000 x rate (Hz) or DC mode 8657A, 99 kHz

max. deviation 8657B, 200 kHz

1.04to 2.06GHz 8000 x rate (Hz) or DC mode 8657B, 400 kHz
max. deviation

Resolution

8657A 100 Hz for deviations < 10 kHz;

1 kHz for deviations ≥ 10 kHz

8657B 100 Hz (200 Hz for carrier frequency >1.04 GHz)

for deviations <20 kHz;
200 Hz (400 Hz for carrier frequency >1.04 GHz)
for deviations >20 kHz

FM rate

Internal 400 Hz and 1 kHz, ±2%
External
(referenced to 1kHz) dc/5 Hz to 100 kHz, 3 dB bandwidth; dc/20 Hz to

50 kHz, 1 dB bandwidth

1. Spurious specifications apply for output levels ≤+4 dBm and f

c

<1.03 GHz when

pulse modulation is installed (8657B) only.

2. 520 MHz to 1.03 GHz for 8657B.

3. FM not specified when peak deviation is >(f

c

–100 kHz).

6

Center frequency accuracy in dc mode

Carrier frequency Center frequency accuracy

0.1 to 130 MHz ±500 Hz
130 to 260 MHz ±125 Hz
260 to 520 MHz ±250 Hz
520 MHz to 1.04 GHz ±500 Hz

1.04 to 2.06 GHz ±1000 Hz

Center frequency <10 Hz per hour drift (typical <3 Hz per
stability in dc mode hour)

Distortion (at internal rates)1<0.5% THD plus noise (typical <1.5% for

all specified deviations and rates)

Sensitivity 1 V

peak

for indicated accuracy, 1 V

dc

when in dc-FM mode

Indicator accuracy (internalrates) <±5% of setting

Incidental AM (peak deviations
<20 kHz, internal rates) fc>500 kHz <0.1% AM

fc>1.03 GHz

2

<0.5% AM

Amplitude modulation

Range

8657A

3

0 to 99%, level ≤+7 dBm, fc≥400 kHz

4

0 to 30%, level ≤+10 dBm, fc≥400 kHz

4

8657B

5

0 to 100%, level ≤+7 dBm, fc≥400 kHz
0 to 30%, level ≤+10 dBm, fc≥400 kHz

Resolution 1%

Rates

Internal 400 Hz and 1 kHz, ±2%
External 20 Hz to 40 kHz (1dB bandwidth);

8657B, typical, 20 Hz to 100 kHz

(3 dB bandwidth)

Distortion (internal rates, level <+7 dBm)

AM depth fc<1.04 GHz fc>1.04 GHz

0 to 30% AM <1.5% 4%
31 to 70% AM <3.0% 4%
71 to 90% AM <4.0% 7%

Sensitivity (typical) 1 V

peak

for indicated accuracy

Indicator accuracy (for depths <90%

and internal rates and levels ≤+7 dBm) <±(2% + 6% of setting)

Incidental phase modulation
(at 30% AM depth, internal rates) <0.3 radians peak

1. 8657A only. FM distortion only specified for deviations up to 25 kHz for

130<fc<260 MHz, and for 260<fc<520 MHz.

2. 8657B only.

3. AM depth is further limited by indicator accuracy specifications.

4. 8657A only. For fc<400 kHz, AM depths of 0 to 30%, levels ≤+7 dBm.

5. 8657B only. When pulse modulation is installed, maximum specified output level

in AM is reduced by 3 dB when fc<1.03 GHz.

7

External modulation input

Front panel BNC, 600 Ω dc-coupled; front panel annunciators indicate 1 V

peak signal ±5%.

Modulating signal output

Internal modulating signal is provided at the front panel BNC connector at

nominally 1 V peak into a 600 Ω resistive load.

Simultaneous modulation

Internal/External AM/FM, FM/AM, AM/AM, FM/FM,

AM/FM/(Pulse1)

Internal/Internal AM/FM
External/External AM/FM

Pulse modulation (Agilent 8657B only)

1

On/off ratio

f

c

≥130 MHz >70 dB

f

c

≥1.03 GHz >95 dB

Rise/fall times

f

c

≥130 MHz >35 ns

f

c

≥1.03 GHz >50 ns

Maximum repetition rate dc to 30 MHz, typical

Level accuracy ±1.0 dB, typical

Duty cycle 0 to 100%, typical (limited by rise/fall

time)

Pulse modulation input BNC, high impedance (internally selec-

table to 50 ohms), can be driven directly
by TTL

Maximum input level ±15 V, typical

Nominal input threshold 1.6 V, typical

Video feedthrough <15%, typical

Pulse time delay

2

On to off 34 ns, typical
Off to on 47 ns, typical

Remote programming

Interface GPIB (IEEE-488)

IEEE-488 functions SH0, AH1, T0, L2, SR0, RL1, PP0, DC1,

DT0, C0, E1

1. 8657B only. Pulse modulation specifications apply for carriers >130 MHz and lev-

els ≤+7 dBm (frequency switching speed typically increases by 30 ms with pulse
modulation on). Additionally, AM is unspecified with pulse modulation turned on
at fc≥1.03 GHz.

2. Time delay between a change in input pulse and carrier response.

General

Operating temperature range 0 to 55 °C

Storage temperature range –40 to +71 °C

Leakage Conducted and radiated interference is

within the requirements of RE02 (and
CE03 for the 8657B, except broadband
conducted below 70 kHz) of MIL STD
461B, and FTZ 1046 (FTZ 1115 for
8657B). Furthermore, RF leakage of less
than 1.0 µV is induced in a two-turn
loop, 2.5 cm in diameter, held 2.5 cm
away from the front surface. (Typical

leakage for the 8657Bis <0.05 µV for
levels <–40 dBm.)

Save/recall/sequence 100 non-volatile registers are available
storage registers to save front panel settings.

Rear-panel SEQ input level TTL low to recall next storage register

contents.

Power requirements 100 or 120 or 220 or 240 volts (+5%,

–10% for 8657A; ±10% for 8657B) from
48 to 440 Hz; 160 VA maximum for
8657A (200 VA maximum for 8657B).
IEC 1010 compliant.

Weight 8657A, net 18.2 kg (40 lb);

shipping 23.6 kg (52 lb)
8657B, net 20.5 kg (45 lb);
shipping 26.0 kg (57 lb)

Dimensions 133 mm H x 425 mm W x 574 mm D

(5.25 in H x 16.75 in W x 22.6 in D)

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Product specifications and descriptions in this
document subject to change without notice.

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