The Marconi TF2304 is an AM/FM modulation meter for servicing and production line testing of radio communication systems, particularly mobile radio transmitters. It delivers automatic tuning and level setting across a wide carrier frequency range, with comprehensive modulation measurement capabilities for both FM and AM signals. Full-scale readings are achieved in approximately 5 seconds.
Technical Specifications
RF Input
• Carrier frequency range: 9 to 12.5 MHz and 18 to 1000 MHz
• Sensitivity: Better than 50 mV to 600 MHz; better than 100 mV to 1000 MHz
• Maximum working input: 1 V r.m.s. (extendable to 7 V r.m.s. with 20 dB switchable pad)
• Maximum safe input: 1 W continuous (7 V into 50 Ω)
• Input impedance: 50 Ω nominal
• Level indicators: LED panel lamps signal over/under-range conditions
FM Measurement
• Deviation ranges: Eight selectable ranges (1.5, 3, 5, 10, 15, 30, 50, 150 kHz full-scale) with ×2 and ×10 extension switches
• Modulation frequency range: 50 Hz to 9 kHz
• Peak or negative deviation indication via front-panel switch
AM Measurement
• Modulation depth ranges: 10%, 30%, and 100% full-scale (usable to 95% modulation depth)
• Modulation frequency range: 50 Hz to 9 kHz
• Depth accuracy: 13% of full-scale deflection on 30% and 100% ranges up to 400 MHz carrier and 80% modulation depth; 0.5 dB accuracy across 50 Hz to 9 kHz at 1 kHz reference
• Peak or trough indication via front-panel switch
Audio Outputs
• AF output: 1 mW nominal into 600 Ω at full-scale (775 mV equivalent); distortion <1% for AM depths to 80%; de-emphasis available with 20 Hz to 15 kHz bandwidth
• IF output: 400 kHz nominal at 100 mV e.m.f. from 1 kΩ source
– Key Features
• Automatic tuning and level control
• Switchable 20 dB attenuator pad for extended input range
• AC mains or rechargeable internal battery operation (190–264 V or 95–130 V, 45–500 Hz)
• Power consumption: Approximately 6 VA
– Typical Applications
Mobile radio transmitter commissioning and production testing; field servicing of AM/FM communication systems; modulation compliance verification.
