Receiver Mode
R&S
®
ESR
170
User Manual 1175.7068.02 ─ 12
Band A
Band B
Band C/D
Band E
Frequency range
<
150
kHz
150
kHz to 30
MHz
30
MHz to 1
GHz
>
1
GHz
Resolution band-
width
200
Hz
9
kHz
120
kHz
1
MHz
Time constant of
the mechanical
device
160
ms
160
ms
100
ms
100
ms
The coupling of the resolution bandwidth to the frequency range with activated CISPR
average detector can be cancelled using the "CISPR RBW uncoupled" softkey.
Regarding measurement time, the relatively long time constants used with CISPR
average and RMS average detector result in long measurement times in order to
obtain a correct measurement result.
●
With unknown signals the measurement time should be at least 1 s. This ensures
correct weighting of pulses down to a pulse frequency of 5 Hz.
●
With unmodulated sinusoidal signals as well as signals with high modulation fre-
quency much shorter measurement times can be used.
●
Slowly fluctuating signals or pulse signals require longer measurement times.
Measurement times shorter than 20 ms
With measurement times shorter than 20 ms the detector weighting changes to plain
average weighting.
When you change the receiver frequency or the attenuation, the R&S
ESR waits until
the the lowpass filter has settled before starting the measurement. The measurement
time in that case depends on the resolution bandwidth and the characteristics of the
signal.
RMS Average detector
The RMS Average detector is a combination of the RMS detector (for pulse repetition
frequencies above a corner frequency) and the Average detector (for pulse repetition
frequencies below the corner frequency). It thus achieves a pulse response curve with
the following characteristics: 10
dB/decade above the corner frequency and 20
dB/
decade below the corner frequency. The average value is determined by lowpass fil-
ters of the 2nd order (simulation of a mechanical instrument).
The detector is used, for example, to measure broadband emissions and may replace
the quasipeak detector in the future.
The filter bandwidth and time constants of the detector are coupled to the receiver fre-
quency.
Measurement Basics
