DSL-300 Dynamic Speech Limiter

The DSL-300 speech limiter is the next generation of the decommissioned popular DSL-100 limiter which includes these new improved features:

  • On board voltage regulation, 28 VDC maximum input voltage
  • Reverse power protection diode
  • Easy to use and calibrate
  • Separate input and output level adjustment potentiometers
  • Limiting level LED indicates when unit is properly limited
  • Easy to connect wire screw posts for DC power and Audio I/O
  • Standard 600 ohm I/O impedance (special order for unbalanced)
  • User configurable I/O impedances other than 600 ohms

This unit is designed to address a common problem in wireless voice communications today:  To maintain quality speech content and control the deviation levels at all times.  Once easily calibrated to your radio transmitter, the DSL-300 will provide +/-12 dB of gain to your transmitted audio levels while ensuring low distortion and no clipping of the audio signal.

Ideal for HF, VHF, UHF and link transmitter applications, all users operating on your radio system will be driving the transmitter with the same audio levels. Users with low deviation levels will sound just as good as the user with the highest level of deviation.  The device does not enable "Hot" users to drive the transmitter into hard limiting (clipping) thereby reducing the quality of their transmission.

When used for telemetry purposes, the DSL-300 provides nominal deviation with both weak and strong signals.  This is an important key feature for linked voice or other telemetry / mixed signal systems.  For example, a user with an average frequency deviation of 2.5 kHz will now be re-transmitting with a typical deviation of 3.0 kHz or whatever you have the DSL-300 calibrated for.   

  • DSL-300
    Limits Audio Deviation     to Specific Levels
    Extremely Fast Attack     and Decay Times
    40 dB Dynamic Limiting     Range
    Far superior to AGC     Processors


Operating Voltage   (12 VDC  Typical) VSUP 11 28 VDC
DC Current Draw ISUP 25 40 mA
*Input Impedance ZIN 600 600 Ohms
**Input Impedance Un-Balanced Zin 10,000 10,000 Ohms
Output Impedance ZOUT 600 600 Ohms
- 3 dB Frequency Bandwidth FBW 300 3,400 Hz
Total Harmonic Distortion Below Limiting THDBL - .01 %
Total Harmonic Distortion Above Limiting THDAL - 2.0 %
Input Limiting Range(Balanced) - -30 +3 dBm
Input Limiting Range (Un-Balanced) - .03 4.0 Volts P-P
Attack Time @ 1 KHz TA - 500 µS
Decay Time TD - 20 mS


Absolute Maximun Ratings

Ambient Operating Temperature 0º to 50º C
Maximum Supply Voltage (diode protection) 28 VDC
Power Dissipation 360 mW


Mechanical Specifications

5.0" 1.75" 0.75"
*The DSL-300 can be configured with different impedances.  Contact us for options.
**Special Order un-balanced unit