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Hub Fan-out

A hub fan-out transceiver test systems is constructed as a star matrix with all ports connected through a central hub. The star configuration limits the number of paths in the matrix to be equal to the number of ports. This type of construction allows for radio-to-radio communication testing. The attenuators can be remotely controlled to simulate static or dynamic environments. Block diagrams for each model are listed in the Documents column of the sortable table.

With the hub configuration, there is a single programmable attenuators between the port and the hub. Two 4 port example block diagrams are listed below the table. The hub fan-out design is the most basic of JFW’s transceiver test systems. It is also the least costly since it uses a minimum number of internal RF components to construct the matrix.

By including RF switches into the construction, you may have multiple hubs. Each port will have an RF switch that is used to select between hubs. The isolation of the switches allows the hubs to act as separate networks.

Please contact us if you do not find a model that meets your requirements. JFW is a customer driven company that does not charge NREs for new models. We strive to deliver test systems that meet your exact requirements so that you do not waste resources for functionality that you do not need.

Ethernet & RS-232 Commands

Click the column headers to sort our online models. For your specific application, please contact JFW for assistance or use our Inquiry Form.

JFW Model #ImpedanceConfigurationdB TotaldB StepFrequency StartFrequency StopControlRF Connectors
50PMA-02950 Ohms8 Ports w/3 Hubs63 dB1 dB0 MHz (DC)2000 MHzEthernet, RS-232SMA
50PMA-03150 Ohms6 Ports w/2 Hubs63 dB1 dB30 MHz3000 MHzEthernet, RS-232SMA
50PMA-04550 Ohms4 Ports w/1 Hub127 dB1 dB0 MHz (DC)1000 MHzManual, Ethernet, RS-232N, SMA
50PMA-07350 Ohms8 Ports w/2 Hubs63 dB1 dB30 MHz2000 MHzManual, Ethernet, RS-232N, SMA, TNC
50PMA-07850 Ohms12 Ports w/2 Hubs127 dB1 dB0 MHz (DC)500 MHzManual, Ethernet, RS-232N, SMA
50PMA-09950 Ohms16 Ports w/6 Hubs63 dB1 dB30 MHz2000 MHzManual, Ethernet, RS-232SMA

4 Port Limited Fan-out System w/ 1 RF Hub

Below are two diagrams. The left diagram shows how all ports are connected to each other. The right diagram shows the attenuator addressing for each path. Each port has its own individually controlled programmable attenuator. A signal transmitted into port #1 is received at the other ports at the following signal levels:

Rx at Port #2 = (Tx into Port #1) – (Attenuator #1) – (loss of Hub) – (Attenuator #2)
Rx at Port #3 = (Tx into Port #1) – (Attenuator #1) – (loss of Hub) – (Attenuator #3)
Rx at Port #4 = (Tx into Port #1) – (Attenuator #1) – (loss of Hub) – (Attenuator #4)

Each programmable attenuator in this example can be varied from 0-127 x 1dB to achieve dynamic RF signal fading between ports. The RF hub is designed with an internal star configuration. This star configuration allows all ports to be simultaneously connected to each other with equal port-to-port loss.

4 Port Limited Fan-out System w/ 2 RF Hubs

The below block diagram shows an example of a 4 port limited fan-out transceiver test system with two RF Hubs. The two RF hubs are used to create two isolated groups of radios. Each port can be connected to either hub by setting the 1P2T RF switches. Once connected to a hub, each programmable attenuator can be varied from 0-127 x 1dB to achieve dynamic RF signal fading between ports.

Capabilities and Options

Custom Models
The models listed in the above table showcase some of our standard transceiver test systems. However, most of JFW’s test system business involves custom designed models. JFW does not charge NREs for custom models. We encourage you to email us your specific requirement to We will respond with a ROM (rough order of magnitude) quote in 1-2 days.

Remote Commands
JFW has standard remote commands for Ethernet, and RS-232 controlled models. The command syntax is simple and allows easy control of the programmable attenuator settings. In addition to our standard commands, JFW can also provide customer specific commands upon request.

Test Software
JFW provides a GUI test program with all Ethernet and RS-232 controlled test systems. The test software for transceiver test systems has all of the remote commands built in for easy testing. In addition to the remote commands, the GUI test program has additional functionality such as keypress, handover, and indefinite handover. Several of our sample test programs are available online.

Remote Control: Ethernet, RS-232
Manual Control: Keypad with display
Enclosures: Benchtop or 19″, 23″, 24″ rack mountable enclosures
Power: AC, Dual redundant AC, or DC powered
RF Connectors: BNC, TNC, SMA, N, etc.
Impedance: 50 Ohm or 75 Ohm

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