Generator, level meter, measuring bridge and spectrum analyzer from 100 Hz to 2400 kHz
To commission or maintain a power line carrier (PLC) link or an FDM system, you need to generate and measure selective levels across the whole carrier band, with the frequency set as carrier ± tone, and to characterize the cable end to end. ET91 generates and measures from 100 Hz to 2400 kHz in 1 Hz steps with 2 ppm ± 1 Hz accuracy, measures selective levels from -120 to +10 dB with ±0.3 dB at 0 dBm, and combines a measuring bridge, a psophometer and a spectrum analyzer in a 1.5 kg hand-held instrument with about 8 hours of battery life.
ET91 key data
- Frequency: generator and receiver from 100 Hz to 2400 kHz in 1 Hz steps with 2 ppm ± 1 Hz accuracy; carrier ± tone setting with carrier from 4 to 2396 kHz in 1 kHz steps and tone from 100 Hz to 3.9 kHz in 1 Hz steps; in tracking modes, the ET91 receiver follows the generator.
- Generator: single frequency, multi-tone test signal (MTTS) or sweep; balanced and coaxial outputs of ~0, 75, 135 (125) and 150 Ω between 10 and 2400 kHz and ~0 and 600 Ω between 100 Hz and 10 kHz; level up to +10 dBm with 0.1 dB resolution and ±0.3 dB accuracy at 0 dBm (f > 200 Hz).
- Receivers: selective measurement from -120 to +10 dB with 20 Hz, 200 Hz, 1.74, 1.95 and 3.1 kHz bandwidths and ±0.3 dB at 0 dBm, in dB, dBm, dBr or mV with PASS/FAIL limits; wideband receiver with six filters, from 100 Hz-4 kHz (-100 to +10 dB) to 24-2400 kHz (-70 to +10 dB).
- Measuring bridge: longitudinal balance (LCL) from 0 to 70 dB under ITU-T O.9, with ±1 dB at 40 dB between 10 and 2400 kHz; return loss from 0 to 40 dB, with ±1 dB at 20 dB between 10 and 500 kHz; crosstalk and loss (NEXT/LOSS) up to 80 dB.
- Noise: psophometer to ITU-T O.41 and wideband filters from 3.1 to 2400 kHz, with measurements from 1 s to 72 h; impulse noise with pulses longer than 500 ns, 1 to 500 mV threshold and up to 65,000 counts.
- Spectrum analyzer: 100 Hz to 2400 kHz in six spans, from 4 kHz with 10 to 20 Hz resolution to 2.4 MHz with 500 Hz to 8 kHz; 300 frequencies, sensitivity down to -140 dBm/Hz and NORM, PEAK, AVG and SAVG evaluation.
- End-to-end measurements: in master-slave mode, two ET91 instruments measure loss, noise at both ends, return loss, impedance, LCL, near-end crosstalk (NEXT) and far-end crosstalk (FEXT), communicating over the line under test.
- Field use: NiMH battery for about 8 h, recharged in less than 3 h with the mains (100-264 V AC) or 12 V adapter; operation from 0 to +40 °C; 200 V DC overvoltage protection; 100 setups and 100 results in memory; USB A and USB B; 224 × 160 × 44 mm and 1.5 kg.
Benefits
Four instruments in one case
Level generator, selective and wideband level meter, measuring bridge and high-resolution spectrum analyzer, all from 100 Hz to 2400 kHz with 1 Hz frequency resolution.
No frequency calculation
The receive frequency is set in carrier ± tone format, exactly as FDM test instructions give it, and in tracking modes the receiver automatically follows the generator.
End-to-end measurements
In master-slave mode, two instruments automatically measure the loss, noise, balance, impedance, return loss and crosstalk of a cable, communicating over the line itself.
Results ready for the report
100 setups and 100 results in memory, PASS/FAIL indication, driver-free USB stick transfer and PC software for protocols and printing.
Applications
- Commissioning and maintenance of PLC links and FDM carrier systems.
- Level, psophometric noise, carrier leak, crosstalk and non-linear distortion in voice channels.
- Cable characterization: loss, longitudinal balance (LCL), impedance and return loss.
- Interference hunting and power spectral density measurement.
About the product
The selective level meter offers five bandwidths -20 Hz, 200 Hz, 1.74, 1.95 and 3.1 kHz- and measures from -120 to +10 dB; the wideband receiver has six band filters. The built-in bridge measures longitudinal balance under ITU-T O.9, return loss and impedance, and the psophometer complies with ITU-T Rec. O.41. Options: group delay, phase jitter, micro interruptions, spectrogram and external 40 dB attenuators.
Technical specifications
| Frequency range | 100 Hz - 2400 kHz in 1 Hz steps; accuracy 2 ppm ± 1 Hz |
| Generator | +10 to -60 dBm (up to +20 dBm below 10 kHz); single frequency, multi-tone or sweep |
| Selective receiver | -120 to +10 dB; bandwidths of 20 Hz, 200 Hz, 1.74, 1.95 and 3.1 kHz; accuracy ±0.3 dB |
| Impedances | 75, 135 (125), 150 Ω and 600 Ω, or high impedance; balanced and coaxial |
| Measuring bridge | LCL 0 - 70 dB; return loss 0 - 40 dB; impedance 50 - 1600 Ω; NEXT/LOSS up to 80 dB |
| Noise | Psophometric (ITU-T O.41) and 8 band filters; impulse noise from 500 ns; 1 s to 72 h |
| Spectrum analyzer | 300 frequencies; down to -140 dBm/Hz; NORM, PEAK, AVG and SAVG |
| Memory and interfaces | 100 setups and 100 results; USB A (USB stick) and USB B (PC) |
| Power and display | NiMH battery, approx. 8 h; 320 × 240 dot TFT |
| Dimensions and weight | 224 × 160 × 44 mm; approx. 1.5 kg |
| Carrier ± tone setting | Carrier 4 - 2396 kHz in 1 kHz steps; tone 100 Hz - 3.9 kHz in 1 Hz steps |
| Bridge accuracy | LCL ±1 dB at 40 dB (10 - 2400 kHz); return loss ±1 dB at 20 dB (10 - 500 kHz) |
| Temperature and protection | Operation 0 to +40 °C (limits -5 to +45 °C); 200 V DC overvoltage protection |
Frequently asked questions
Which software options extend the ET91?
Group delay distortion with a 37-tone signal (0 to 10 ms with 1 µs resolution, under ITU-T O.81), phase jitter under ITU-T O.91 (0.2 to 30° p-p) with ±30 Hz frequency error, micro interruptions from 0.6 ms to over 1 min over 4 min to 72 h, the spectrogram and the spectral trace as reference.
Can the ET91 measure levels above +10 dB?
Yes, with the optional external 40 dB attenuator, coaxial or balanced: with it, the instrument measures levels up to +40 dB between 10 and 2400 kHz with ±0.5 dB accuracy.
Is the receive frequency calculated by hand for FDM systems?
No. Carrier and tone are entered separately, and in tracking mode the receiver tunes by itself to the carrier ± the generator frequency.
Are two instruments needed to test a cable?
For automatic end-to-end measurements, yes: one works as master and the other as slave. Return loss or impedance are measured with a single instrument.
How are results moved to the PC?
With a USB stick, without installing drivers, or by connecting the instrument to the PC through the USB B port and using the PC software.
How long does the battery last?
About 8 hours. It recharges inside the instrument in less than 3 hours with the mains adapter or the 12 V car adapter.
