EMI Test Receivers R&S ESIB

The EMI Test Receivers ESIB 7/26/40 from Rohde & Schwarz have been renamed.

The ESIB family of EMI test receivers combines the flexibility and speed of spectrum analyzers with the large dynamic range required for EMI measurements in conformance with standards.
The ESIB family comprises three models with different upper frequency limits:

ESIB7 (20 Hz to 7 GHz)
ESIB26 (20 Hz to 26.5 GHz)
ESIB40 (20 Hz to 40 GHz)

The upper frequency limit of the ESIB26 and ESIB40 can be extended up to 110 GHz by means of external mixers (option FSE-B21).
All three models are characterized by

high sensitivity
excellent large-signal immunity
low measurement uncertainty
high measurement speed

Measurements to standard
The ESIB carries out measurements in conformance with all industrial and military EMI standards such as CISPR, EN, VDE, ANSI, FCC, BS, ETS, VCCI, MIL-STD, VG, DEF-STAN, DO160 and GAM EG13. It goes without saying that the ESIB family complies with the basic standard, i.e. CISPR16-1 or VDE0876, which places stringent requirements on receiver dynamic range.

Overview measurement

Test routines oriented to practical requirements
During the various development phases of a product, different measurements are performed as required for each stage. The ESIB family offers appropriate features and routines for the different development stages.
Early in development, functional measurements play the predominant role. While EMI measurements are important right from the beginning to avoid redesigns, the ESIB at this stage primarily functions as a highgrade spectrum analyzer.
The ESIB is outstanding for its low inherent noise, high intermodulation suppression and low SSB phase noise. Modulation analysis of analog or digital signals is possible with the optional Vector Signal Analyzer FSE-B7. Moreover, the ESIB provides all test routines offered by modern spectrum analyzers, such as noise measurement, phase noise measurement, channel and adjacent-channel power measurement and time-domain measurement, as known from the FSE family.
As development progresses, EMI measurements become more and more important, for example on modules and their interfaces. Measurements are frequently carried out using sensors, probes or current transformers. Interference analysis and referencing of results to limit values are important. Here, too, the ESIB family meets all relevant requirements in terms of performance, functionality and economy of operation:

Fast overview measurements with linear or logarithmic frequency scale in spectrum analyzer mode (sweep mode) or in test receiver mode (scan mode) with tuning in user-defined frequency steps with selectable measuring times per step
Bandwidths conforming to CISPR16-1 (200 Hz, 9 kHz and 120 kHz), to MIL-STD (10 Hz to 1 MHz) and 10 MHz, and analyzer bandwidths between 1 Hz and 10 MHz, selectable in steps of 1, 2, 3 and 5
Pulse weighting using quasi-peak, peak and average detectors. The detectors operate in parallel and can be switched in as required
User-selectable transducer factors for the output of results in the correct unit. Transducer factors for practically any number of transducers can be stored on the internal hard disk. Active transducers are powered and coded via a socket on the ESIB front panel
User-definable limit lines with linear or logarithmic frequency scale; limit lines are stored on the internal hard disk
Time-domain measurements at up to 50 ns resolution for interference source analysis

The excellent characteristics and functions of the ESIB family come into their own when compliance with relevant EMI standards is to be verified on the finished product. This may involve limit values for RFI voltage measurements using artificial mains networks, for RFI field-strength measurements by means of test antennas, or for RFI power measurements with absorbing clamps.
Especially measurements using artificial mains networks and absorbing clamps put the pulse-handling capability of the RF input to a severe test. The ESIB solves this problem by means of a second, pulse-protected input for the frequency range 20 Hz to 1 GHz. In the case of the ESIB7, for example, this input can handle pulses with voltages up to 1500 V and powers up to 30 mWs without any damage being caused. Pulses generated by artificial mains networks during phase switching or during RFI power measurements on ignition cables using absorbing clamps pose no problem.
The input bandwidth of the front end is limited by preselection filters to reduce the total voltage level at the input mixer to an extent compatible with the wide dynamic range required for quasi-peak detection in the CISPR frequency range. Up to 2 MHz, the ESIB family uses fixed-tuned filters; from 2 MHz to 1000 MHz, the preselection filters operate as tracking filters.
An autorange function is available for the automatic setting of attenuation and gain in the RF and IF signal paths. This function ensures the correct combination of attenuation and gain depending on the test level or any overload of a signal stage caused by pulses or sinusoidal signals. So the operator is not burdened with the internal workings of the test receiver.
To measure extremely small voltage levels occurring, for example, in EMI measurements on vehicle antennas in line with CISPR 25, the ESIB family offers a 20-dB-preamplifier from 9 kHz to 7 GHz. The preamplifier is located between the RF preselection and the input mixer to protect against overload. With this preamplifier, the inherent noise of ESIB is lowered to such an extent that the RFI field strength obtained in an overview measurement using the peak detector, a log-periodic antenna (e.g. HL223) and a 10 m connecting cable clearly remains below the EN55022 quasi-peak limit (Fig. 1).

Fig. 1

Fig. 1

Fig. 2 shows the SCAN table stipulated for commercial EMI measurements as a function of the prescribed CISPR bandwidths.
Fig. 2
Fig. 2

To achieve high sensitivity in measurements to MIL-STD-461D RE 101 in the frequency range from 30 Hz, the unavoidable feedthrough of the 1st LO at the input mixer is suppressed by self-alignment of the mixer. ESIB consequently features sufficient inherent noise suppression with respect to relevant limit values even at the lower frequency limit (Fig. 3).
Fig. 3
Fig. 3

Definition of standard test sequences
To meet the requirements of relevant standards, measurements over various frequency ranges and band-widths have to be performed, using different step sizes and measurement times or different receiver settings regarding RF attenuation and preamplification. It must also be possible to configure a scan matched to DUT characteristics. For this purpose, the ESIB offers a user-configurable scan table with up to 10 subranges.
Calibration values for transducer factors of absorbing clamps or antennas, for example, are stored in tables and can be switched on as required. The transducer factors can also be combined into transducer sets, for example to display the interference spectrum in the correct unit dBµV/m in measurements with an antenna and a connecting cable (Fig. 4).
Fig. 4
Fig. 4

EMI emissions are usually measured in two steps. An overview measurement made with the peak detector identifies critical emissions above or close to limit values (Fig. 5). In a second measurement with the prescribed detectors (quasi-peak and average to CISPR) and an appropriate measurement time, the critical frequencies are checked for compliance with limit values. The ESIB family supports this procedure by two independent measurement windows on the screen.

Split-screen display
Critical emissions can be measured with numerical display of frequency and level as with classic receivers. Bargraphs provide an analog display of measured values for the various detectors simultaneously and in different colours (Fig. 5). By coupling the marker in the overview spectrum to the receiver frequency, emissions can be measured fast and reliably in line with standards.
Fig. 5
Fig. 5

In the second window, the operator can zoom in on the displayed trace (Fig. 6).
Zooming is effected either based on stored measured data or by means of a new measurement with the selected detectors. If stored data are used, all stored values can be displayed. For this, the ESIB can store up to 250000 measured values per trace in background operation. This considerably reduces measurement time, since no new measurement is needed to make a detailed analysis.
Fig. 6
Fig. 6

Listen, view, measure
To analyze the spectrum and to exclude ambient noise, such as originating from sound or TV broadcast transmitters or the like, it is expedient to select single frequencies by means of the markers, tune the receiver frequency to the marker frequency, and activate the audio path with the built-in AM/FM demodulator by switching on the loudspeaker or headphones. Acoustic identification is very frequently and successfully used in EMI signal analysis, all the more so since manual pre/postmeasurements and interactive operation support this approach.

Documentation of results
Practically any type of printer can be used for the documentation of results. The ESIB runs under Windows NT, so all printers for which Windows drivers are available can be employed.
Results can not only be output to a printer but also stored on a floppy disk or the internal hard disk in common Windows formats like EMF, WMF or BMP. The data can be integrated into commercial word processing programs for the generation of test reports.
High accuracy
In the frequency range up to 1 GHz, the ESIB performs level measurements with an accuracy of ±1 dB. This is clearly better than the value of ±2 dB speci-fied by CISPR16-1, and is achieved by individual correction factors stored on all modules affecting measurement uncertainty. The operator can run calibration routines for the frequency response, display linearity and signal path gain correction for the various instrument settings, thus ensuring low measurement uncertainty under all specified environmental conditions.
The required calibration sources are connected internally so that autocorrection is possible even in system applications without any external equipment such as cables being required. Pulse weighting with the peak, average and quasi-peak detectors is implemented in the ESIB for the first time fully digitally by means of gate arrays and signal processors. This makes for the best possible reproducibility of results and does away with the discharge times between measurement periods occurring with analog detectors. As a result, measurement times are reduced considerably.
Selftest
The built-in selftest supports fault localization down to module level. With individual correction tables being stored on each module, defective modules can be replaced largely without any adjustment or additional instruments. Downtimes and repair costs are reduced to a minimum.
System integration
The fast data processing of the ESIB makes it an ideal choice for use in automatic measurement systems. The IEC/IEEE-bus command set (IEC 625-2) conforms to SCPI (1994.0).
With a second IEC/IEEE-bus card (option FSE-B17), the ESIB can be used as a test system controller. This is possible because, with the operating system Windows NT, an integrated controller function is provided as standard which allows the use of a wide variety of Rohde&Schwarz software packages.
This enables the implementation of complete measurement systems without the need for an additional controller, which saves space and cost.
Fit for the future
The ESIB family can be upgraded by a wide variety of options to extend its range of applications and add extra functionality without requiring additional instruments. The Tracking Generator FSE-B10 or FSE-B11 (with I/Q modulator) from 9 kHz to 7 GHz makes it easy to measure shielding effectiveness or filter transfer functions.
The option FSE-B7 allows the analysis of signals with digital or analog modulation. The ESIB is the first instrument suitable for both EMI measurements and the complete measurements of RF parameters, for example of GSM mobile or base stations. The firmware options FSE-K10 for GSM mobile stations and FSE-K11 for GSM base stations support the complete range of RF measurements in full compliance with ETSI standards.

EMI Test Receivers R&S ESIB EMI measurements up to 40 GHz conforming to standards


		Characteristics The EMI Test Receivers ESIB 7/26/40 from Rohde & Schwarz have been renamed. The ESIB family of EMI test receivers combines the flexibility and speed of spectrum analyzers with the large dynamic range required for EMI measurements in conformance with standards. The ESIB family comprises three models with different upper frequency limits: ESIB7 (20 Hz to 7 GHz) ESIB26 (20 Hz to 26.5 GHz) ESIB40 (20 Hz to 40 GHz) The upper frequency limit of the ESIB26 and ESIB40 can be extended up to 110 GHz by means of external mixers (option FSE-B21). All three models are characterized by high sensitivity excellent large-signal immunity low measurement uncertainty high measurement speed Measurements to standard The ESIB carries out measurements in conformance with all industrial and military EMI standards such as CISPR, EN, VDE, ANSI, FCC, BS, ETS, VCCI, MIL-STD, VG, DEF-STAN, DO160 and GAM EG13. It goes without saying that the ESIB family complies with the basic standard, i.e. CISPR16-1 or VDE0876, which places stringent requirements on receiver dynamic range. Overview measurement Test routines oriented to practical requirements During the various development phases of a product, different measurements are performed as required for each stage. The ESIB family offers appropriate features and routines for the different development stages. Early in development, functional measurements play the predominant role. While EMI measurements are important right from the beginning to avoid redesigns, the ESIB at this stage primarily functions as a highgrade spectrum analyzer. The ESIB is outstanding for its low inherent noise, high intermodulation suppression and low SSB phase noise. Modulation analysis of analog or digital signals is possible with the optional Vector Signal Analyzer FSE-B7. Moreover, the ESIB provides all test routines offered by modern spectrum analyzers, such as noise measurement, phase noise measurement, channel and adjacent-channel power measurement and time-domain measurement, as known from the FSE family. As development progresses, EMI measurements become more and more important, for example on modules and their interfaces. Measurements are frequently carried out using sensors, probes or current transformers. Interference analysis and referencing of results to limit values are important. Here, too, the ESIB family meets all relevant requirements in terms of performance, functionality and economy of operation: Fast overview measurements with linear or logarithmic frequency scale in spectrum analyzer mode (sweep mode) or in test receiver mode (scan mode) with tuning in user-defined frequency steps with selectable measuring times per step Bandwidths conforming to CISPR16-1 (200 Hz, 9 kHz and 120 kHz), to MIL-STD (10 Hz to 1 MHz) and 10 MHz, and analyzer bandwidths between 1 Hz and 10 MHz, selectable in steps of 1, 2, 3 and 5 Pulse weighting using quasi-peak, peak and average detectors. The detectors operate in parallel and can be switched in as required User-selectable transducer factors for the output of results in the correct unit. Transducer factors for practically any number of transducers can be stored on the internal hard disk. Active transducers are powered and coded via a socket on the ESIB front panel User-definable limit lines with linear or logarithmic frequency scale; limit lines are stored on the internal hard disk Time-domain measurements at up to 50 ns resolution for interference source analysis The excellent characteristics and functions of the ESIB family come into their own when compliance with relevant EMI standards is to be verified on the finished product. This may involve limit values for RFI voltage measurements using artificial mains networks, for RFI field-strength measurements by means of test antennas, or for RFI power measurements with absorbing clamps. Especially measurements using artificial mains networks and absorbing clamps put the pulse-handling capability of the RF input to a severe test. The ESIB solves this problem by means of a second, pulse-protected input for the frequency range 20 Hz to 1 GHz. In the case of the ESIB7, for example, this input can handle pulses with voltages up to 1500 V and powers up to 30 mWs without any damage being caused. Pulses generated by artificial mains networks during phase switching or during RFI power measurements on ignition cables using absorbing clamps pose no problem. The input bandwidth of the front end is limited by preselection filters to reduce the total voltage level at the input mixer to an extent compatible with the wide dynamic range required for quasi-peak detection in the CISPR frequency range. Up to 2 MHz, the ESIB family uses fixed-tuned filters; from 2 MHz to 1000 MHz, the preselection filters operate as tracking filters. An autorange function is available for the automatic setting of attenuation and gain in the RF and IF signal paths. This function ensures the correct combination of attenuation and gain depending on the test level or any overload of a signal stage caused by pulses or sinusoidal signals. So the operator is not burdened with the internal workings of the test receiver. To measure extremely small voltage levels occurring, for example, in EMI measurements on vehicle antennas in line with CISPR 25, the ESIB family offers a 20-dB-preamplifier from 9 kHz to 7 GHz. The preamplifier is located between the RF preselection and the input mixer to protect against overload. With this preamplifier, the inherent noise of ESIB is lowered to such an extent that the RFI field strength obtained in an overview measurement using the peak detector, a log-periodic antenna (e.g. HL223) and a 10 m connecting cable clearly remains below the EN55022 quasi-peak limit (Fig. 1). Fig. 1 Fig. 2 shows the SCAN table stipulated for commercial EMI measurements as a function of the prescribed CISPR bandwidths. Fig. 2 To achieve high sensitivity in measurements to MIL-STD-461D RE 101 in the frequency range from 30 Hz, the unavoidable feedthrough of the 1st LO at the input mixer is suppressed by self-alignment of the mixer. ESIB consequently features sufficient inherent noise suppression with respect to relevant limit values even at the lower frequency limit (Fig. 3). Fig. 3 Definition of standard test sequences To meet the requirements of relevant standards, measurements over various frequency ranges and band-widths have to be performed, using different step sizes and measurement times or different receiver settings regarding RF attenuation and preamplification. It must also be possible to configure a scan matched to DUT characteristics. For this purpose, the ESIB offers a user-configurable scan table with up to 10 subranges. Calibration values for transducer factors of absorbing clamps or antennas, for example, are stored in tables and can be switched on as required. The transducer factors can also be combined into transducer sets, for example to display the interference spectrum in the correct unit dBµV/m in measurements with an antenna and a connecting cable (Fig. 4). Fig. 4 EMI emissions are usually measured in two steps. An overview measurement made with the peak detector identifies critical emissions above or close to limit values (Fig. 5). In a second measurement with the prescribed detectors (quasi-peak and average to CISPR) and an appropriate measurement time, the critical frequencies are checked for compliance with limit values. The ESIB family supports this procedure by two independent measurement windows on the screen. Split-screen display Critical emissions can be measured with numerical display of frequency and level as with classic receivers. Bargraphs provide an analog display of measured values for the various detectors simultaneously and in different colours (Fig. 5). By coupling the marker in the overview spectrum to the receiver frequency, emissions can be measured fast and reliably in line with standards. Fig. 5 In the second window, the operator can zoom in on the displayed trace (Fig. 6). Zooming is effected either based on stored measured data or by means of a new measurement with the selected detectors. If stored data are used, all stored values can be displayed. For this, the ESIB can store up to 250000 measured values per trace in background operation. This considerably reduces measurement time, since no new measurement is needed to make a detailed analysis. Fig. 6 Listen, view, measure To analyze the spectrum and to exclude ambient noise, such as originating from sound or TV broadcast transmitters or the like, it is expedient to select single frequencies by means of the markers, tune the receiver frequency to the marker frequency, and activate the audio path with the built-in AM/FM demodulator by switching on the loudspeaker or headphones. Acoustic identification is very frequently and successfully used in EMI signal analysis, all the more so since manual pre/postmeasurements and interactive operation support this approach. Documentation of results Practically any type of printer can be used for the documentation of results. The ESIB runs under Windows NT, so all printers for which Windows drivers are available can be employed. Results can not only be output to a printer but also stored on a floppy disk or the internal hard disk in common Windows formats like EMF, WMF or BMP. The data can be integrated into commercial word processing programs for the generation of test reports. High accuracy In the frequency range up to 1 GHz, the ESIB performs level measurements with an accuracy of ±1 dB. This is clearly better than the value of ±2 dB speci-fied by CISPR16-1, and is achieved by individual correction factors stored on all modules affecting measurement uncertainty. The operator can run calibration routines for the frequency response, display linearity and signal path gain correction for the various instrument settings, thus ensuring low measurement uncertainty under all specified environmental conditions. The required calibration sources are connected internally so that autocorrection is possible even in system applications without any external equipment such as cables being required. Pulse weighting with the peak, average and quasi-peak detectors is implemented in the ESIB for the first time fully digitally by means of gate arrays and signal processors. This makes for the best possible reproducibility of results and does away with the discharge times between measurement periods occurring with analog detectors. As a result, measurement times are reduced considerably. Selftest The built-in selftest supports fault localization down to module level. With individual correction tables being stored on each module, defective modules can be replaced largely without any adjustment or additional instruments. Downtimes and repair costs are reduced to a minimum. System integration The fast data processing of the ESIB makes it an ideal choice for use in automatic measurement systems. The IEC/IEEE-bus command set (IEC 625-2) conforms to SCPI (1994.0). With a second IEC/IEEE-bus card (option FSE-B17), the ESIB can be used as a test system controller. This is possible because, with the operating system Windows NT, an integrated controller function is provided as standard which allows the use of a wide variety of Rohde&Schwarz software packages. This enables the implementation of complete measurement systems without the need for an additional controller, which saves space and cost. Fit for the future The ESIB family can be upgraded by a wide variety of options to extend its range of applications and add extra functionality without requiring additional instruments. The Tracking Generator FSE-B10 or FSE-B11 (with I/Q modulator) from 9 kHz to 7 GHz makes it easy to measure shielding effectiveness or filter transfer functions. The option FSE-B7 allows the analysis of signals with digital or analog modulation. The ESIB is the first instrument suitable for both EMI measurements and the complete measurements of RF parameters, for example of GSM mobile or base stations. The firmware options FSE-K10 for GSM mobile stations and FSE-K11 for GSM base stations support the complete range of RF measurements in full compliance with ETSI standards.


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