A70 4-Port And A75 2-Port Low Frequency Extension (Lfe) Board - Keysight N5224B Series Service Manual

Theory of Operation
Synthesized Source Group Operation

A70 4-Port and A75 2-Port Low Frequency Extension (LFE) Board

Provides a 900 Hz to 100 MHz LFE signal for measurements. Refer to
www.keysight.com/find/pna.
The Low Frequency Extension (LFE) option in the PNA consists of an LFE board
A70 4-port or A75 2-port) and a new 4-Port bias combiners (A70-A74). See
also "A38–A41 60-dB Source Step Attenuators and A71–74 Bias Tee
Combiners (Optional)" on page
This board is designed to extend the frequency bandwidth at the low end,
down to 900 Hz. And, the high end of the LFE board is 100 MHz. Between
10 MHz and 100 MHz either LFE or non-LFE mode can be used.
The inputs and outputs connectors of the LFE board:
PNA 2 ports:
Inputs:
— LFE output of the Synthesizer #1 board J102 connected to LFE board J20.
— LFE output of the LO board J102 connected to LFE board J18.
— The main connector of the Motherboard bus to LFE board connector J1.
Outputs:
— LF output J2, 900 Hz - 100 MHz, Port 1, to be connected to the bias
combiner Port 1.
— LF output J3, Port 2, to be connected to the bias combiner Port 2.
— 4 IF outputs J11, J12, J13, J14, to be connected to the LFE inputs of the IF
MUX board: A, B, R1, R2.
PNA 4 ports:
The inputs are:
— LFE output of the LO board J102 connected to LFE board J18.
— LFE output of the Synthesizer #1 board J102 connected to LFE board J20.
— LFE output of the Synthesizer #2 board J102 connected to LFE board J21.
— The main connector of the Motherboard bus to LFE board connector J1.
The outputs are:
— LF output J2, 900 Hz - 100 MHz, Port 1, to be connected to the bias
combiner Port 1.
— LF output J3, Port 2, to be connected to the bias combiner Port 2.
— LF output J4, Port 3, to be connected to the bias combiner Port 3.
— LF output J5, Port 4, to be connected to the bias combiner Port 4.
5-28
5-46.
Keysight N5224B/25B Service Guide