Modulation Meter 2305

Marconi Instruments, Marconi-Ekco (MI, MEI)

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  • Year
  • 1985 ?
  • Category
  • Service- or Lab Equipment
  • Radiomuseum.org ID
  • 364408

 Technical Specifications

  • Number of Transistors
  • Semiconductors present.
  • Semiconductors
  • Main principle
  • Special principle (see notes)
  • Wave bands
  • Wave Bands given in the notes.
  • Power type and voltage
  • Alternating Current supply (AC) / 45-440 Hz, 105-120; 210-240 Volt
  • Loudspeaker
  • - For headphones or amp.
  • Material
  • Metal case
  • from Radiomuseum.org
  • Model: Modulation Meter 2305 - Marconi Instruments, Marconi-
  • Shape
  • Tablemodel with Push Buttons.
  • Dimensions (WHD)
  • 425 x 152 x 535 mm / 16.7 x 6 x 21.1 inch
  • Notes

  • The Marconi Modulation Meter 2305 (also known as the IFR/Aeroflex 2305) is a high-performance, microprocessor-controlled test instrument designed for precise and versatile measurements on modulated radio frequency (RF) signals.

    Developed in the late 1970s/1980s, the 2305 was a foundational tool for engineers working in fixed and mobile communications, broadcasting, and general RF equipment maintenance.

    Functional Description
    The Marconi 2305 is essentially a highly refined, multi-band superheterodyne receiver integrated with sophisticated digital measurement circuitry.

    1. Automatic Operation: Its key feature is automatic tuning and ranging.4 When a signal is applied, the instrument automatically locks onto the carrier frequency and selects the appropriate measurement range for the modulation present.
    2. Architecture: Internally, the signal passes through an attenuator, a mixer (often utilising a step recovery diode-based harmonic mixer), and into an IF (Intermediate Frequency) stage.
    3. Measurement: Dedicated analog detector boards separate AM, FM, & ΦM components of the signal, which are then processed by the internal microprocessor (e.g., an NEC D8085AHC.
    4. Output: A high-quality demodulated output is provided, allowing the operator to monitor the audio or baseband signal on an external device like an oscilloscope.
    5. Calibration: An internal calibrator is included, which performs automatic calibration checks upon power-up to maintain measurement accuracy without relying on constant manual adjustments.

    Key Technical Specifications and Capabilities

    FeatureSpecification: Capability
    Carrier Frequency Range: 50 kHz to 2.32 GHz
    Modulation Types: AM, FM, ΦM
    FM Deviation: Up to 500 kHz
    AM Depth: Up to 99.9%
    Basic Accuracy: ±5% for modulation measurements
    Tuning: Automatic Tuning (to the strongest signal) or Manual tuning via keypad.
    RF Power: Direct indication of power levels from 10 mW to 1 W.
    Additional Measurements: Performs measurements for frequency, RF power, frequency response, and signal-to-noise ratio.
    Interface: GPIB (General Purpose Interface Bus, IEEE 488) for remote, automated control and integration into test systems.
    Protection: Against accidental overloads up to 25 W,

     

  • Net weight (2.2 lb = 1 kg)
  • 13.5 kg / 29 lb 11.8 oz (29.736 lb)
  • Mentioned in
  • - - Manufacturers Literature (Technical Manual, TM 11-6625-3146-14 (1985))
  • Author
  • Model page created by Miguel Bravo-Cos. See "Data change" for further contributors.

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