This distribution amplifier is intended to distribute a low noise 10 MHz frequency reference. The amplifier has one input and seven outputs, all on BNC connectors. The input is coupled through a series LC network allowing the use of inputs with a DC offset. The input source impedance is 50Ω at 10 MHz.
The input is conditioned by a limiter which provides several advantages. It removes amplitude modulation from the input signal, outputs have fixed amplitude, and input noise that occurs more than 50 mV away from the zero-crossing is blocked. Virtually any waveform with a duty cycle near 50% may be used as an input.
The input limiter is followed by a bandpass filter and a fixed gain amplifier. This signal is passed to seven output amplifiers, each of which is followed by a low pass filter and an output transformer. All of the outputs have 50Ω source impedance and provide a 1Vrms (+13 dBm) sine wave into a 50Ω load.
There are four indicator LEDs. The “power” LED indicates that the unit has AC power. The “signal” LED indicates that an input signal is present. The “overload” LED indicates that the input signal has excessive amplitude. The “fault” LED indicates one or more of these conditions: no input signal, excessive input signal, no output signal, or low internal DC power supply.
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Sine wave outputs (+13dbm)
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Amplitude leveling
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Low additive phase noise
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High channel-to-channel isolation
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High return loss
