The Brandywine Communications Model FDU-240 offers the user the most requested and reliable frequency distribution features in one time and frequency distribution unit. The base unit is a dual input, 24 output frequency distribution amplifier suited for 5MHz or 10MHz. Each output is monitored and will set the alarm if an output fault is detected.
For enhanced phase noise performance an optional clean up oscillator is installed between the rear panel inputs and the inputs of the transfer switch. A clean up oscillator may be installed between both Input A and Input B inputs or only on Input A.
When fitted with the optional clean up oscillators, the stability of the outputs are the same as that of the input(s). This is accomplished by disciplining the clean up oscillator(s) to the reference input(s).
The FDU-240 is one of Brandywine's low phase noise distribution units that has a three-position front panel switch chooses automatic operation or may be used to manually select one of the two input sources. When the AUTO mode is selected the AUTO indicator will be illuminated and Input A will be used if it is available. Should Input A fail Input B will be chosen automatically. Indicators show the status of the inputs and which input has been selected.
| Reference Frequency Inputs: | |
| Connector | Two rear panel BNC's |
| Amplitude | 0.5 Vrms - 1 Vrms |
| Input Impedance | 50 Ohms |
| Frequency | 10 MHz |
| Fault Discrete Input: | |
| Number of Inputs | 2 |
| Connector | DB9 |
| Level | TTL |
| Active Level | Link selectable, high or low |
| Sine Wave Outputs: | |
| Number of Outputs | 24 |
| Connector | BNC |
| Frequency (MHz) | Same as input |
| Level | +13, +/- 2 dBm into 50 Ohms |
| SSB Phase Noise (with clean-up osc. Option) | |
| Offset (Hz) | dBc/Hz |
| 1 | -60 |
| 10 | -110 |
| 100 | -140 |
| 1,000 | -150 |
| 10,000 | -155 |
| Harmonics | 30 dBc |
| Spurious | -80 dBc |
| Stability | |
| Without clean-up option | Same as input |
| With clean-up option | +/- 3x10-9, 0 |
| Physical/Environmental | |
| Temperature | |
| Operating | 0 to + 50°C |
| Storage | -40 to +85°C |
| Humidity | To 95% non-condensing |
| Dimensions | 19 inch Rack Mount, 1.73 inches high (1U) |
| 14.5 inches deep | |
| Weight | 7.5 lb typical |
 FDU-240 | Data Sheet |
| FDU-240 (022000001) | User Manual |
| FDU-240 (022000002) | User Manual |
