The ODU (Out-door Unit) is a microwave RF device that is used in point-to-point microwave communication links. It is responsible for converting data from the IDU (In-door Unit) into an RF signal for transmission. It also converts the RF signal from the far end to suitable data to transmit to the IDU. The ODU has several functions, including:
- Signal processing: The ODU performs various signal processing tasks, such as filtering, equalization, and noise reduction.
- Frequency conversion: The ODU converts the data signal from the IDU to an RF signal at the desired frequency. This is necessary because the data signal is typically digital, while the RF signal is analog. The ODU uses a frequency synthesizer to generate the desired RF signal.
- Power amplification: The ODU amplifies the RF signal to a level that is sufficient for transmission over the desired distance. The amount of amplification required depends on the distance between the ODUs and the amount of attenuation that the signal will experience as it travels through the atmosphere.
- Modulation: The ODU modulates the RF signal with the data signal. This means that the ODU adds the data signal to the RF signal in a way that allows the data to be recovered at the far end.
- Demodulation: The ODU demodulates the RF signal at the far end. Signal processing: The ODU performs various signal processing tasks, such as filtering, equalization, and noise reduction. These tasks are necessary to improve the quality of the signal and to reduce the effects of interference.
The ODU supports the following features:
- Various channel spacing.
- Various modulation formats.
- Adaptive modulation (AM) function.
- Adjustment of TX/RX frequencies through software.
- Adjustment of TX power through software.
- Temperature detection.
- TX power detection.
- RX power detection.
- Received Signal Strength Indicator (RSSI) interface: The ODU has an RSSI interface, which indicates the RX power in voltage.
- Mute or TX off transmission.
- Automatic Transmit Power Control (ATPC).
- Remote Transmission Power Control (RTPC).
- Automatic Gain Control (AGC) function of received signals:
- The ODU automatically adjusts the channel gain according to the level of received signals.
The frequency range that ODUs (Outdoor Units) support depends on the specific model of ODU. However, most ODUs support frequencies in the range of 4-42 GHz. Some of the most supported frequency bands for ODUs include:
- 6 GHz
- 7 GHz
- 8 GHz
- 10 GHz
- 11 GHz
- 13 GHz
- 15 GHz
- 18 GHz
- 23 GHz
- 26 GHz
- 28 GHz
- 32 GHz
- 38 GHz
- 42 GHz
ODUs also support different RF channel bandwidths. The most common RF channel bandwidths for ODUs are 3.5 MHz, 7 MHz, 14 MHz, 28 MHz, 40 MHz, and 56 MHz. The RF channel bandwidth determines the amount of data that can be transmitted over the ODU link.
