TEKBOX TBMDA7 Modulated Wideband Driver Amplifier Instructions

TEKBOX TBMDA7 Modulated Wideband Driver Amplifier

Specifications

• Product Name: TBMDA7 Modulated Wideband Driver Amplifier
• Application: General-purpose gain block, signal source for immunity testing, driving near field probes
• Features:
  • CW amplifier (modulation off)
  • 1 kHz, 80% AM modulation
  • 1 kHz, 50% duty cycle pulse modulation
  • 217 Hz, 12.5% duty cycle pulse modulation

Electrical Specifications

Frequency [MHz]| Gain @ -15dBm [dB]| Gain @ -12dBm [dB]| Gain @ -10dBm [dB]| Gain @ -8dBm [dB]
---|---|---|---|---

Power Supply
The current consumption of the TBMDA7 is 800mA. Supply the TBMDA7 through a USB 3.0 port or a mobile phone charger with an output current capability of 1A or higher. Connector: Mini-USB-C

Applications
The TBMDA7 Modulated Wideband Driver Amplifier can be used for various applications including general-purpose gain block, signal source for immunity testing, and driving near field probes.

TEM Cell Field Strength
To measure the field strength inside the TEM cell, use the provided formulas based on distance and power input to approximate the field strength at different frequencies.

Product Usage Instructions

1. Connect the TBMDA7 to a power source using a USB 3.0 port or a mobile phone charger with an output current of 1A or higher.
2. Adjust the input power level based on the desired frequency and modulation type.
3. Use appropriate connectors to interface with the signal source for immunity testing or driving near field probes.

Introduction

The TBMDA7 modulated wideband driver amplifier is designed to provide an inexpensive signal source for immunity testing of electronic building blocks and products. It operates in the frequency range from 1 GHz to 3 GHz and is designed to be driven by the tracking generator output of spectrum analyzers. With a 1dB compression point of 350 mW avg. and a saturated output power of 500 mW avg., it can boost the output power of a tracking generator to drive Tekbox near field probes in order to find the sensitive spot of an electronic circuit or to create electric fields up to 150V/m CW, 80V/m AM when driving the Tekbox TEM Cell TBTC0, 80V/m CW, 45V/m AM when driving the TBTC1, 40V/m CW, 25 V/M AM when driving the TBTC2 or 27V/m CW, 15V/m AM when driving the TBTC3. Test signals for immunity testing can be CW, AM or PM. The TBMDA7 provides built in modulation capability to generate 1 kHz AM or PM signals. In PM mode, the TBMDA7 can also generate a 217 Hz Signal with 12.5% duty cycle in order to simulate mobile phone TDMA noise.

Application:

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

Features:

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

Electrical Specifications

Technical Data:

• Frequency range: 1 GHz – 3 GHz
• RF Input / Output: 50 Ohm, SMA female; DC supply: Mini-USB-C connector
• Nominal supply Voltage: 5V, typ. 800mA; maximum supply voltage 5.5V.
• Nominal input power: -10 dBm to – 8 dBm; maximum input power: -5 dBm continuous, -3 dBm max.
• Operating temperature range : -20°C to 50°C
• Harmonics: < -10 dBc typ. @ 1.5 GHz
• Harmonics: < -15 dBc typ. @ 1.5 GHz
• Internal modulation frequency AM: 1 kHz ±10%
• Internal modulation frequencies PM: 1 kHz ±10%, 217 Hz ±20%
• Duty cycle, PM: 50% ±10% @ 1 kHz; 12.5% ±20% @ 217 Hz

Output Power, Saturated; measured with -8 dBm input power

Frequency [MHz]| 1000| 1500| 2000| 2500| 3000
Saturated Output Power [dBm]| 24,35| 26,3| 28| 29,3| 27,3
Saturated Output Power [W]| 0,272| 0,427| 0,631| 0,851| 0,537

Table 1 – TBMDA7 saturated output power

Output Power, P1dB; measured with -10 dBm input power

Frequency [MHz]| 1000| 1500| 2000| 2500| 3000
P1dB [dBm]| 22,1| 25| 27,1| 27,3| 26,4
P1dB [W]| 0,162| 0,316| 0,513| 0,537| 0,437

Table 2 – TBMDA7 saturated output power

Input power: -8/-10/-12/-15 dBm

Frequency [MHz]| 1000| 1250| 1500| 1750| 2000| 2250| 2500| 2750| 3000
Gain @ -15dBm [dB]| 36,7| 39,5| 40,7| 41,3| 41,9| 42,6| 42,1| 40,1| 38,4
Gain @ -12dBm [dB]| 36,1| 38,6| 39,7| 40,6| 41,4| 42,1| 41,8| 39,9| 38,2
Gain @ -10dBm [dB]| 35,3| 37| 38,1| 39,4| 40,3| 40,9| 40,9| 39,5| 38
Gain @ -8dBm [dB]| 33,9| 35,2| 36,4| 37,7| 38,7| 39,5| 39,6| 39,3| 37,9

Table 3 – TBMDA7 gain

Power supply
The current consumption of the TBMDA7 is 800mA. Supply the TBMDA7 through a USB 3.0 port or a mobile phone charger with an output current capability of 1A or higher.

Applications

TEM Cell field strength

A typical pre compliance set up for immunity testing is typically not sophisticated enough to measure the real field strength inside the TEM cell. However, the field strength can be approximated mathematically.
The E-field (V/m) between septum and lower (upper) wall of a TEM cell is E = V/d where V is the RMS voltage of the applied signal and d is the distance between septum and lower (upper) wall. This is based on the simplified assumption that the E field would be perfectly homogenous/evenly distributed. A more practical formula is E = V*Cor/d where Cor is a correction factor for the average field strength over the volume of the DUT derived from the analysis of the field distribution over the cross section of the cell.
Assuming the DUT is placed in the center of the cell and in the middle between bottom wall and septum, we can however use the simplified formula with sufficient accuracy.

• TBTC0: d = 2.8 cm -> E[V/m] = (√(P50Ω))35.7
• TBTC1: d = 5 cm -> E[V/m] = (√(P50Ω))20
• TBTC2: d = 10 cm -> E[V/m] = (√(P50Ω))10
• TBTC3: d = 15 cm -> E[V/m] = (√(P50Ω))6.66

The power P in the formulas above hast to be entered in [Watt] P [W] = 0.001*(10^ (P[dBm]/10))

Frequency [MHz]| Input power [dBm]| Output power [dBm]| Field strength TBTC0 [V/m]| Field strength TBTC1 [V/m]| Field strength TBTC2 [V/m]| Field strength TBTC3 [V/m]
---|---|---|---|---|---|---
1000| -10| 23| 112| 63| 31| n.a
1100| -10| 24.3| 131| 73| 37| n.a
1200| -10| 24.7| 137| 77| 38| n.a
1300| -10| 24.6| 135| 76| n.a| n.a
1400| -10| 25.3| 146| 82| n.a| n.a
1500| -10| 25.3| 147| 83| n.a| n.a
1600| -10| 26.2| 163| 91| n.a| n.a
1700| -10| 26.3| 164| 92| n.a| n.a
1800| -10| 26.4| 168| 94| n.a| n.a
1900| -10| 26.9| 176| 99| n.a| n.a
2000| -10| 27.5| 189| 106| n.a| n.a
2100| -10| 27.8| 196| 110| n.a| n.a
2200| -10| 28.1| 202| n.a| n.a| n.a
2300| -10| 28.3| 206| n.a| n.a| n.a
2400| -10| 28.7| 216| n.a| n.a| n.a
2500| -10| 28.4| 210| n.a| n.a| n.a
2600| -10| 28.3| 208| n.a| n.a| n.a
2700| -10| 27.6| 192| n.a| n.a| n.a
2800| -10| 27.5| 190| n.a| n.a| n.a
2900| -10| 26.9| 176| n.a| n.a| n.a
3000| -10| 26.5| 168| n.a| n.a| n.a

Table 4 – calculated field strength for TBMDA7 driving Tekbox TEM cells

• The calculations above refer to a CW signal.
• To achieve the same RMS field strength with an AM signal, 5.1 dB higher peak power is required.
• To achieve the same RMS power with 50% duty cycle pulse modulation, 3 dB higher peak power is required.

PC Software for immunity testing

The Tekbox EMCview SW supports immunity pre-compliance testing with a feature for automated tracking generator control. This significantly simplifies immunity testing, especially in case of repeated testing during debugging and validation of DUT modifications/improvements. Tekbox EMCview currently supports Rigol, Siglent, Owon, UNI-T, Teledyne, BK-Precision, R&S FPC and FPH series spectrum analyzers.

Figure 8 – screenshot of the tracking generator control feature of EMCview

WARNING: Never connect the output of the TBMDA7 directly to the input of a spectrum analyzer. Check the maximum input ratings of the spectrum analyzer and protect it with an appropriate attenuator.

Example:
Rigol DSA815 – maximum input power rating: +20dBm

Ordering Information

20dB attenuator with N-connectors, USB cable,

History

FAQ

Q: What is the recommended input power level for optimal performance?
A: For saturated output power, it is recommended to use -8 dBm input power. For P1dB output power, -10 dBm input power is ideal.

Q: Can the TBMDA7 be powered using a standard USB port?
A: It is recommended to use a USB 3.0 port or a mobile phone charger with an output current of 1A or higher to power the TBMDA7 for optimal performance.

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