SAGE-300 Speech Audio Gain Equalizer

The SAGE-300 will enhance and balance the tone quality of your communication repeater system by enabling you to cut or boost, by 10 dB, three audio speech bands. The low frequency cutoff is at 250 Hz, which prevents sub-audible CTCSS tones from being passed on for equalization. Measured at the - 3dB points, the audio speech passband is from 275 to 4,400 Hz. Three separate trim potentiometers enable the user to boost the amplitude of the low (275 - 1,000 Hz), mid (1,000 - 2,600 Hz), and high (2,000 - 4,400 Hz) bands.

Ideal for HF, VHF, UHF and link transmitter applications, the SAGE-300 will compensate for the short comings in audio section of your communications system. Many microphones, link radios, and transmitters, have less then optimal audio characteristics. Audio degradation problems are compounded in linked or interconnected systems. The SAGE-300 enables you to easily balance your audio to ensure the highest quality of communications. Audio performance is significantly improved on all modes of modulation, including: SSB, AM, wide and narrow band FM. Total harmonic distortion is less than 0.01% @ 1 kHz.

When used for telemetry purposes it will allow the audio path to be bandwidth limited and it will improve DTMF twist problems associated with interconnected systems. The SAGE-300 also enables users to adjust Narrow Band FM radios to meet the new EIA de-emphasis specification (6dB per octave de-emphasis curve). Many receivers being used today do not meet this specification, which results in un-natural and hard to understand audio.

  • Sage-300
    3 Bands Designed for
        Audio Equalization
    Speech 0 to 8 Volt P-P     Input
    Easy to Install
    Low Power    Consumption


Operating Voltage   (12 VDC  Typical) VSUP 10 18 VDC
DC Current Draw ISUP 7 12 mA
Input Impedance ZIN 10K 10k Ohms
Output Impedance ZOUT 150 150 Ohms
- 3 dB Frequency Bandwidth FBW 275 4,400 Hz
Low Frequency Boost BW FBW_L 275 1,000 Hz
Mid Frequency Boost BW FBW_M 1,000 2,600 Hz
High Frequency Boost BW FBW_H 2,000 4,400 Hz
100 Hz CTCSS Filter Cut   -25   dB
150 Hz CTCSS Filter Cut   -15   dB
200 Hz CTCSS Filter Cut   -10   dB
250 Hz CTCSS Filter Cut   -6   dB
Low Band Center Frequency Fc_L 500 500 Hz
Mid Band Center Frequency Fc_M 1,700 1,700 Hz
High Band Center Frequency FC_H 2,800 2,800 Hz
Total Harmonic Distortion @ 1 kHz (+/- 0 dB) THD - 0.01 %
Audio Input Amplitude VIN 0 8.0 V P-P
Gain AG -10 +10 dB


Absolute Maximun Ratings

Ambient Operating Temperature 0º to 70º C
Maximum Supply Voltage (diode protection) 18 VDC
Power Dissipation 220 mW


Mechanical Specifications

1 - 1/2" 2 - 1/4" 0.50"