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I/Q Analyzer

R&S

ESR

474User Manual 1175.7068.02 ─ 12

Figure 7-1: Block diagram illustrating the R&S

ESR signal processing

Maximum number of samples

The maximum number of samples for RF input is 200 MS.

7.5.1 Sample Rate and Maximum Usable Bandwidth (RF Input)

Definitions

●

Input sample rate (ISR): the sample rate of the useful data provided by the con-

nected instrument to the R&S ESR input

●

(User, Output) Sample rate (SR): the sample rate that is defined by the user (e.g.

in the "Data Aquisition" dialog box in the "I/Q Analyzer" application) and which is

used as the basis for analysis or output

●

Usable I/Q (Analysis) bandwidth: the bandwidth range in which the signal

remains undistorted in regard to amplitude characteristic and group delay; this

range can be used for accurate analysis by the R&S ESR

For the I/Q data acquisition, digital decimation filters are used internally. The passband

of these digital filters determines the maximum usable I/Q bandwidth. In consequence,

signals within the usable I/Q bandwidth (passband) remain unchanged, while signals

outside the usable I/Q bandwidth (passband) are suppressed. Usually, the suppressed

signals are noise, artifacts, and the second IF side band. If frequencies of interest to

you are also suppressed, you should try to increase the output sample rate, since this

increases the maximum usable I/Q bandwidth.

Relationship between sample rate and usable bandwidth

The diagram Figure 7-2 shows the maximum usable I/Q bandwidths depending on the

user sample rates.

As a rule, the usable bandwidth is proportional to the output sample. Yet, when the I/Q

bandwidth reaches the bandwidth of the analog IF filter (at very high sample rates), the

curve breaks.

Working with I/Q Data

R&S ESR Series User Manual

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