Specifications

28
Figure 19. Receive site configuration with external mixing using the N5264A PNA-X
measurement receiver.
Select the LO Source
The recommended microwave mixers use fundamental mixing from 300 MHz to 18 GHz,
andharmonicmixingforfrequenciesabove18GHz.Thus,anLOsourcethatoperates
over the frequency range of 0.3 to 18 GHz will be adequate for all frequencies of
operation.AlargeselectionofsourcesisavailablefortheLOsource.Inmanysituations
thePNASeriescansupplytheLOsignalsincetheLOsourcesonlyneedtooperateover
the frequency range of 0.3 to 18 GHz.
TheLOsourcemustbeabletosupply0to6dBmpoweratthe85309BLOinput.To
determine whether the source has enough power, cable losses must first be considered.
LossofLOcablesisdependentonfrequency;lowerfrequencieshavelowerlossperunit
length,andhigherfrequencieshavehigherloss.ThereforethemaximumLOfrequency
utilizedwillresultinthemaximumcableloss.ThemaximumLOfrequencyisdependent
on the frequency specified for the antenna range and whether fundamental or harmonic
mixingisused.Thereisatrade-offbetweenLOfrequencyandsystemsensitivity.
Fundamental mixing provides the lowest conversion loss in the mixer, and the best
systemsensitivity.HarmonicmixingallowslowerLOfrequenciestobeused(withlonger
cable lengths), but has higher conversion loss in the mixer, and less system sensitivity.
Beforecalculatingcableloss,youmustfirstdeterminetheLOfrequency.IfusingPNA
SeriesOptionH11,theLOfrequencymustbesetsothatan8.33MHzIFisproduced.The
PNASeries’LOisoffsetfromitsRFby8.33MHzautomaticallyifthePNAisoperated
below 20 GHz and frequency offset is turned off. Refer to “Setting up the PNA LO for an
8.33 MHz IF”, later in this document, for more information.
ThePNASeries’internalLOcanbeaccessedthrougharearpaneloutputportif
Option H11 is installed. Its frequency range is limited to 1.7 GHz to 20 GHz. The signal
on the rear panel is very low power and always requires an amplifier to achieve the
requiredpowerlevelatthe85309B.ThefrontpanelRFcanonlybeusedastheLOfor
the 85309B if it is not used as the system RF.
85309B
85320B
Reference mixer
85320A
Test mixer
LO in
PNA-X measurement receiver
with Option 108
Pout = 19 dBm
Pout = 19 dBm
Pin = 8 to 16 dBm
Pin = 8 to 16 dBm
Pin = 0 to 6 dBm
RF out (P
S
)
LO in
RF in
Pin < 26 dBm
RF in
Pin < 26 dBm
P
TM
P
RM
L
1
L
2
L
3
L
4
L
6
L
5
+23 dBm–9 dBm
7.605634 MHz
Rear input
Option 020
+15 dBm–10 dBm7.605634 MHzIF inputs
Damage
level
Max input
(.1 dB)
FreqInput