The Marconi TF2304-900S is an FM/AM modulation meter engineered for production and field testing of mobile radio transmitters. It delivers automatic tuning and level control across dual frequency bands, with switchable input attenuation and comprehensive modulation analysis across 9 Hz to 1000 MHz operation.
Technical Specifications
Carrier frequency coverage spans 9–12.5 MHz and 18–1000 MHz with automatic tuning. RF input sensitivity reaches better than 50 mV to 600 MHz and better than 100 mV to 1000 MHz. Maximum working input is 1 V RMS, extendable to 7 V RMS with a 20 dB switchable attenuator. Input impedance is 50 Ω nominal. Safe input handling at 1 W (7 V into 50 Ω) continuous. Automatic level control with front-panel indicators warns of excessive or insufficient signal levels. Reading time with automatic tuning is approximately 5 seconds.
FM deviation measurement employs eight selectable ranges: 1.5, 3, 5, 10, 15, 30, 50, and 150 kHz full-scale, with x2 and x10 multiplier factors. FM deviation accuracy is typically 0.5% and less than 1% up to 150 kHz. AM depth measurement offers 10%, 30%, and 100% full-scale ranges (usable to 95%). AM depth accuracy is within 13% of full-scale on the 30% and 100% ranges at carrier frequencies to 400 MHz and 1 kHz modulation. Modulation frequency range for both FM and AM spans 50 Hz to 9 kHz, with ±0.5 dB flatness across this band relative to 1 kHz.
Switched de-emphasis is available on demodulated output. IF output at 400 kHz nominal delivers 100 mV EMF from a 1 kΩ source. AF output (demodulated) provides 1 mW nominal into 600 Ω at full-scale meter deflection, with 20 Hz to 15 kHz bandwidth.
– Key Features
• Dual-band tuning: 9–12.5 MHz and 18–1000 MHz
• Eight FM deviation ranges with multiplier extension
• Automatic level control with high/low indicators
• 20 dB switchable input attenuator
• IF and demodulated audio outputs
• AC mains (190–264 V or 95–130 V, 45–500 Hz) with ~6 VA consumption
• Optional rechargeable 21 V battery (8 hours nominal operation) with built-in charger and monitoring
– Typical Applications
Mobile radio transmitter commissioning and verification. Production line modulation conformance testing. Carrier frequency and modulation depth troubleshooting.
