Tektronix RSA2200A, Руководство пользователя

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Product Overview
RSA2203A & RSA2208A User Manual
1- 7
Converts the RF signal, input through the front-panel INPUT connector, into a
20 MHz IF signal. This converter processes signals up to 3 GHz for RSA2203A
and 8 GHz for RSA2208A by IF conversions in three stages. A 10 MHz
oscillator provides a high-accuracy reference for all stages of IF conversion. The
converter also adjusts signals for A/D conversion using a low-noise amplifier,
fine-tuning attenuator, and anti-alias filter. The output signal from the down
converter is sent to the IF sampling A/D converter described below.
The IF analog output from the down converter enters the A/D converter through
the fine-tuning attenuator, low-noise amplifier, and anti-alias filter, to be
converted into a digital signal. The sampling rate of the A/D converter is
51.2 MHz with a resolution of 14 bits.
The digital down converter splits the real signal from the A/D converter into
complex (I and Q) components and limits the frequency span of the resulting
signal.
The down converter performs span and center frequency fine-tuning. This
converter consists of two primary stages. In the baseband (Option 05), the first
stage converts a 0 to 20 MHz real signal into a complex signal of

10 MHz.
The second stage converts frequency to set any center frequency.
A decimating filter between stages changes the span by effectively reducing the
sampling rate. A 503 tap FIR filter and four stage comb filter allows extremely
accurate filtering with minimal spurious emissions.
The data streams from the digital down converter are then divided into frames
and saved in data memory.
A high-speed 2 MB standard SDRAM stores spectrum data. For each data point,
I and Q data use 2 bytes. This memory can store 500 frames for 1 waveform =
1024 points of analysis. The memory is accessed from the system controller
through the ISA/PCI bridge.
3 GHz / 8 GHz
Down Converter
IF Sampling A/D Converter
Digital Down Converter
Data Memory