TBMDA4 - Modulated Wideband Power Amplifier

 Tekbox TBMDA4 - Modulated Power Amplifier

TBMDA4 - Modulated Power Amplifier

The TBMDA4 modulated wideband power amplifier is designed in order to create an inexpensive signal source for immunity testing of electronic building blocks and products. It is designed to be driven by the tracking generator output of spectrum analyzers. With an input power range of -5 dBm…0 dBm, it can boost the output power of a tracking generator up to 5W. With a frequency range from 100 kHz to 50 MHz, it is an ideal complement to the TBMDA3, which covers 10 MHz to 1 GHz. The TBMDA4 is ideal to drive Tekbox near field probes in order to find the sensitive spot of an electronic circuit or to create electric fields up to 550V/m when driving the Tekbox TEM Cell TBTC0, 300V/m when driving the TBTC1, 150V/m when driving the TBTC2 or 100V/m when driving the TBTC3. Test signals for immunity testing can be CW, AM or PM modulated. Consequently, the TBMDA4 provides built in modulation capability to generate 1 kHz AM or PM signals. In PM mode, the TBMDA4 can also generate a 217 Hz Signal with 12.5% duty cycle in order to simulate mobile phone TDMA noise.


  • CW amplifier (modulation off)
  • 1 kHz, 80% AM modulation
  • 1 kHz, 50% duty cycle pulse modulation
  • 217 Hz, 12.5% duty cycle pulse modulation


Input / Output:50 Ohm, N female
Supply Voltage range:110 V…240 V
Supply power consumption:20 W
Operating temperature range:-20°C to 50°C
Frequency range:100 kHz – 50 MHz
1dB output compression point @ 1 MHz:+35.5 dBm typ.
1dB output compression point @ 10 MHz:+36 dBm typ.
1dB output compression point @ 50 MHz:+36.5 dBm typ.
2nd harmonic, 20 MHz, Pout=36dBm:< - 15 dBc typ.
2nd harmonic, 25 MHz, Pout=30dBm:< - 20 dBc typ.
3rd harmonic, 25 MHz, Pout=36dBm:< - 25 dBc typ.
3rd harmonic, 25 MHz, Pout=30dBm:< - 30 dBc typ.
Total harmonic distortion:
6.7% @25MHz, Pout=27dBm typ.
8.5% @25 MHz, Pout=30 dBm typ.
12% @25 MHz, Pout=33 dBm typ.
15% @25 MHz, Pout=36 dBm typ.
Third order intercept point:
+53dBm, @25 MHz, ∆ f = 200kHz typ.
Noise figure:9 dB
Internal modulation frequency AM:1 kHz ±20%
Internal modulation frequencies PM:1 kHz ±10%, 217 Hz ±20%
Duty cycle, PM:50% ±10% @ 1 kHz; 12.5% ±20% @ 217 Hz
Maximum ratings:
Maximum input power:0 dBm

The output of the TBMDA4 is quite tolerant to output mismatch, however open or shorted load is not recommended, potentially can cause damage.

Small Signal Gain (measured with Pin = - 20 dBm):

50 kHz

100 kHz

500 kHz

1 MHz

5 MHz

10 MHz

25 MHz

50 MHz

70 MHz

39.3 dB

44.9 dB

47.1 dB

47.2 dB

47.3 dB

47.5 dB

48.6 dB

49.9 dB

44.5 dB



  • General-purpose power amplifier
  • Signal source for immunity testing, driving near field probes 
  • Signal source for immunity testing, driving TEM Cells



Jason Lin,
2019年5月16日 上午4:10