Additional Features:
- Selective Level Meter
- Frequency range: 200(50) Hz to 1.62 MHz
- Frequency error limits: ±3 x 10¯6 ±1 Hz
- Input impedance, coaxial: 75Ω, high impedance; balanced: 75, 150(135), 600Ω and high impedance
- Display range, Zο = 75Ω, bandwidth 25 Hz Selective, f ≥10 kHz: -120 to 20 dBm
- Display resolution: 0.01 dB
- Bandwidth, selectable: 25 Hz, 1.74 kHz(1.95kHz), 3.1kHz
- Ambient temperature, nominal range: 0 to 50°C
- Selective and wideband measurements
- Synthesizer gives high frequency accuracy
- Frequency settings: numeric entry by means of keyboard, in steps, or in quasi-analog mode
- Frequency search; AFC
- Absolute and relative measurements
- Digital level and voltage display and autoranging
- Quasi-analog bar graph shows result trends
- Integral demodulator and loudspeaker
- Memory for 100 setups/fixed frequencies
- 100 results can be stored
- Powered by internal batteries or external a.c. adaptor/charger
The compact, handy, battery-powered SMP-33 Selective Level Meter has been designed as multi-function in-service test set for CF transmission systems with up to 300 voice channels. The lower frequency limit of (50)200 Hz makes measurements in the audio and voice range possible. From 50 to 200 Hz, measurements are possible but with lower accuracy and sensitivity.
Selective and wideband measurements of level and noise at balanced and coaxial test points can be made. If higher levels are to be measured, e.g. power line carrier systems, the necessary external attenuator is available as an accessory.
The instrument can therefore handle practically all field test that are carried out during the installation, maintenance and monitoring of CF systems as operated by PTTs, the railways or public utility companies in the energy sector for example. The SPM-33 forms a complete FDM test set with the PS-33 level generator.
As far as easy operation is concerned, the instruments can be compared with larger, up-market bench equipment. By using high scale integration and SMD (surface mounted devices), the size and volume of both units are far below that of conventional sets used in similar applications.
The tuning frequency is produced by a synthesizer, so ensuring high frequency accuracy and stability. The frequency can be entered by means of a numeric keypad, in steps or in the quasi-analog mode. The result is either displayed as an absolute level or voltage or as a level difference, i.e. the difference between a measured value and a reference value. Results are shown on a digital display which has a maximum resolution of 0.01 dB.
Autoranging has been provided to make operation even easier. A fast bar graph indicates level trends (resolution 0.1 dB). One hundred setups/fixed frequencies can be stored to reduce the work involved in routine measurements. The SPM-33 can be run on its own internal batteries which are monitored to prevent incorrect results when the battery goes low. The SPM-33 can be powered from an a.c. adaptor/charger LNT-1 when measurements of some duration are being made.
When the SPM-33 is switched on a selftest is run, this is followed by a calibration routine. Display symbols indicate if a fault is present, and the fault type.
