20 GHz Microwave Counter 2440

Marconi Instruments, Marconi-Ekco (MI, MEI)

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  • Année
  • 1985 ?
  • Catégorie
  • Appareils de mesure et de dépannage (matériel de labo)
  • Radiomuseum.org ID
  • 364409

 Spécifications techniques

  • No. de transistors
  • Semi-conducteurs présents
  • Semi-conducteurs
  • Principe général
  • Principe spécial
  • Gammes d'ondes
  • Bandes en notes
  • Tension / type courant
  • Alimentation Courant Alternatif (CA) / 50 - 400 Hz, 105-120; 210-240 Volt
  • Haut-parleur
  • - - Pas de sortie basse fréquence
  • Matière
  • Boitier métallique
  • De Radiomuseum.org
  • Modèle: 20 GHz Microwave Counter 2440 - Marconi Instruments, Marconi-
  • Forme
  • Modèle de table avec boutons poussoirs.
  • Dimensions (LHP)
  • 215 x 108 x 338 mm / 8.5 x 4.3 x 13.3 inch
  • Remarques

  • The Marconi Microwave Counter 2440 is a versatile, microprocessor-controlled frequency counter primarily designed for high-frequency (microwave) applications but offering a continuous measurement range starting from the audio band. It was engineered for speed, accuracy, and tolerance to complex modulated signals prevalent in communications.

    Features and Architecture

    1. Three-Channel Input System
    The counter manages its extremely wide frequency range by routing the signal to one of three specialized input channels:

    • Channels A & B handle the lower, direct-count frequencies. Channel A includes a switchable Low-Pass Filter to improve noise immunity when measuring low-frequency signals.
    • Channel C employs the sophisticated Harmonic Heterodyne Conversion technique under microprocessor control to down-convert the microwave signal to an intermediate frequency (IF) that can be processed by the lower-frequency counting circuits.

    2. High Modulation Tolerance
    A crucial feature for communication applications, the 2440 can accurately measure the carrier frequency even when the signal is heavily modulated:

    • FM Tolerance: Up to 30 MHz peak-to-peak frequency modulation.
    • AM Tolerance: Up to 40% amplitude modulation depth.

    3. Automatic Amplitude Discrimination
    The counter includes automatic amplitude discrimination, which allows it to measure the strongest signal present on an input channel while ignoring adjacent, weaker signals or spurious responses. This is a form of inherent selectivity, simplifying measurements in crowded RF environments.

    4. Frequency Offset Facility
    A standard feature, the OFFSET function allows the user to program an offset frequency to be added or subtracted from the measured frequency. This is useful for testing transmitters or receivers where the actual operating frequency is shifted by a fixed intermediate frequency (IF).

    5. Microprocessor Control
    The instrument utilises a microprocessor to manage channel switching, auto-ranging, resolution settings, display functions, and both local keypad control and remote GPIB operation, making it suitable for both bench use and automated test systems.

    Key Technical Specifications

    Parameter Specification
    Frequency Range: 10 Hz to 20 GHz (Continuous)
    Input Channels: 3 independent input channels (A, B, and C)
    Channel A: 10 Hz to 100 MHz (Direct count, High Z)
    Channel B: 50 MHz to 600 MHz (Direct count, 50 Ω)
    Channel C: 600 MHz to 20 GHz (Direct count, High Z)
    Measurement Principle: Harmonic Heterodyne Conversion (for microwave band)
    Resolution: 0.1 Hz to 10 kHz
    Display: 9-digit Liquid Crystal Display
    Acquisition Time: Typically 200 ms (Fast response for high-frequency measurements)
    High Frequency Stability: Accuracy dependent on timebase (often high-stability OCXO option available)
    Remote Control: Fully GPIB (IEEE 488) programmable.
  • Poids net
  • 5.5 kg / 12 lb 1.8 oz (12.115 lb)
  • Littérature
  • - - Manufacturers Literature (Service manual H 52440-900M (1985))
  • Auteur
  • Modèle crée par Miguel Bravo-Cos. Voir les propositions de modification pour les contributeurs supplémentaires.

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