Specifications
Specifications describe the instrument’s warranted performance over the temperature range of 0°C to +55°C unless otherwise
noted. Typical values for the specified parameters represent probable but non-warranted performance. Nominal values provide
useful but non-warranted information about functional performance.
Test Receiver
The following system specifications apply when the 85685A RF preselector (RFP) operates with the 8566B or 8568B spectrum
analyzer (SA) and with or without the 85650A quasi-peak adapter (QPA). The test receiver system is fully GPIB programmable.
Refer to the specific instrument data sheets for more detailed information.
Test receiver frequency
Parameter Specification
Frequency range
RFP bypass1
20 Hz – 1.5 GHz with 8568B
20 Hz – 2.0 GHz with 8566B
20 Hz – 18 GHz (nominal) with 8568B
SA frequency resolution 1 Hz
SA frequency accuracy ±(tuned frequency x freq. reference error) Hz for SA zero span
SA frequency reference error Settability2 < 10-8, Drift < 2 x 10-7/year
SA Frequency selectivity3
3 dB resolution BW 10 Hz – 3 MHz in 1, 3, 10 sequence
Test receiver amplitude
Parameter Specification
Measurement range -150 to +30 dBm (-43 to +137 dBµV) (nominal)
Gain compression (0 dB atten. for RFP and SA
Inside RFP passband
Outside RFP passband
< 1 dB (nominal) for input ≤ -30 dBm
< 1 dB (nominal) for input ≤ +10 dBm
Displayed average noise level
(0 dB atten. for RFP and SA 10 Hz resolution BW)
< -132 dBm (-25 dBµV) for input 9 kHz – 1 MHz4
< -150 dBm (-43 dBµV) for input 1 – 1500 MHz
< -147 dBm (-40 dBµV) for input ≤ 2.0 GHz
Broadband signal sensitivity5,6
(0 dB atten. for RFP and SA, 10 Hz resolution BW)
< 31 dBµV/MHz (nominal) for input < 1 MHz4
< 13 dBµV/MHz (nominal) for input = 1 – 1500 MHz
< 16 dBµV/MHz (nominal) for input ≤ 2.0 GHz
Second harmonic distortion (0 dB atten. for RFP and SA)
For -35 dBm input signal:
Within RFP passband
Outside RFP passband
< -55 dBc (nominal), Equiv. SOI = +20 dBm
< -75 dBc (nominal), Equiv. SOI = +40 dBm
Third order intermodulation (0 dB atten. for RFP and SA)
For two -35 dBm input signals:
Within RFP passband
Outside RFP passband
< -40 dBc (nominal), Equiv. SOI = -15 dBm
< -110 dBc (nominal), Equiv. SOI = +20 dBm
Residual responses
(RFP input terminated, 0 dB atten. for RFP and SA
< -90 dB for input 2 kHz – 1 MHz
< -112 dB for input ≥1 MHz
< -120 dB (typical) for input ≥1 MHz
Amplitude accuracy6
(+10° to + 30°C, 10 dB SA atten. 0 –20 dB RFP atten.)
RFP bypass
±2.0 dB for input < 1.0 GHz
±3.0 dB for input ≥1.0 GHz
SA specification plus:
± 0.5 dB (nominal) for input ≤ 2.0 GHz
± 1.0 dB (nominal) for input > 2.0 GHz

400:The standard HP 8566B requires that the power linefrequency be 50 or 60 Hz. Option 400 allows the instrument to operate with a 400 Hz power line
frequency. 

608:608-IN-LG 4-40-THD HEAT SINK SGL TO-5/TO-39-CS TRANSISTOR

856:Series Portable Spectrum Analyzers require option 008, or FW date code