EMI Test Receivers ESBI and ESMI combine the top-class specifications of Rohde&Schwarz EMI test receivers with the speed of Rohde& Schwarz spectrum analyzers. The integral measurement and analysis functions simplify and speed up all measurements to the relevant commercial and military standards such as CISPR, VDE, FCC, EN, VCCI, MIL-STD, VG, DEF-STAN, BS, DO 160, GAM-EG13.
All these test receivers satisfy the exacting requirements of CISPR standard 16-1 (08.93) and VDE standard 0876. They are thus highly suitable for all compliance tests in line with commercial standards. ESBI and ESMI provide excellent characteristics for EMI measurements. They can however also be used as top-class spectrum analyzers for general laboratory applications (further typical characteristics see data sheets PD 756.4808/.8384 and .7120).

Main features

• RF attenuation switchable in wide range and small steps
• Refined preselection
• Very large frequency range for EMI measurements
• Low-noise preamplifier with wide dynamic range
• High-level mixer for IF conversion
• Additional filters ahead of IF preamplifier to avoid overloading due to broadband interference in IF section
• Highly linear envelope detector with dynamic range of 70 dB in addition to 110 dB logarithmic converter in analyzer path
• Five parallel detectors for peak, minimum, quasi-peak, average and RMS weighting
• DC logarithmic converter with dynamic range of 70 dB
• Overload detectors at the mixers and in the test channel to avoid incorrect measurements

Measurement capabilities

RF dynamic range
The EMI test receivers feature a large dynamic range and high sensitivity. Moreover, the test receiver settings completely conform to CISPR requirements, ie the dynamic range is large enough in all CISPR ranges to allow correct weighting of single pulses. Refined preselection filtering provides the required large dynamic range for wideband signals. A low-noise preamplifier, which can be switched after the preselector, is used to increase sensitivity. To measure high-energy pulses,
a second input is provided which can handle pulses in the frequency range from 20 Hz to 200 MHz. An automatic overload detector checks sensitive points in the signal path.

Signal analysis
EMI test receivers have a variety of maximum, minimum, average, rms and quasi-peak detectors for simultaneous signal analysis. Built-in AM/FM demodulators allow audio monitoring of interference signals. A pulse calibration source for checking the CISPR weighting curves is provided in addition to the built-in sine calibration source, thus ensuring extremely high measuring accuracy. A tracking generator for all kinds of EMC measurements is also provided.

Operation

OVERVIEW mode
 In this mode, the whole interference spectrum is displayed on the screen of the test receiver. The IF resolution bandwidths can be adjusted to CISPR standards; the IF selectivity has also a quasi-analog setting mode to optimize the sweep time. The interference spectrum can be displayed on the screen using a linear or logarithmic frequency scale. A maximum of eight different limit lines can be displayed on the screen. Out-of-limit values are automatically detected and displayed.

Fast, flexible scan
In the SCAN mode, ESBI and ESMI are directly comparable with a conventional test receiver:
• In addition to measurements at the selected frequency, a scan can be started
• Measurements are made automatically between start and stop frequency and at a selectable step size
• Manual adjustments while the scan is in progress and repeat measurements over selectable subranges reduce the time required for measurements

To conform to relevant standards, measurements over various frequency ranges and bandwidths have to be made. For this purpose, the user can define a variety of frequency ranges in a configuration table. Measurements are then made over these subranges using the selected bandwidth, measurement time, step size, etc.

Split-screen display
The results are output in two windows obtained by splitting the screen display horizontally. Different trace memories, and so the results from different detectors, can be displayed in the upper and the lower window. The split-screen display is ideal for showing narrowband and broadband signals separately.

Automatic compensation for transducers
The test results are always displayed with correct units. The transducers designed for the Rohde & Schwarz test receivers are, of course, suitable for use with ESBI or ESMI. Correction factors entered in a transducer table are used to automatically compensate for the frequency dependence of the transducer factor. A maximum of four such tables are available and can also be combined.