8/13/2015
Digital Microwave Communication Equipment ODU, IDU, Dish, Antenna
Digital Microwave Communication Equipment Home > Electronics > Microwave & Radar > Digital Microwave Communication Equipment
Microwave Equipment Category
Trunk Microwave Equipment High cost, large transmission capacity, more stable performance, applicable to long haul and trunk transmission RF, IF, signal processing, and MUX/DEMUX units are all indoor. Only the antenna system is outdoor.
http://www.daenotes.com/electronics/microwaveradar/digitalmicrowavecommunicationequipment
1/8
8/13/2015
Digital Microwave Communication Equipment ODU, IDU, Dish, Antenna
All Outdoor Microwave Equipment • All the units are outdoor. • Installation is easy. • The equipment room can be saved.
SplitMount Microwave Equipment (1)
http://www.daenotes.com/electronics/microwaveradar/digitalmicrowavecommunicationequipment
2/8
8/13/2015
Digital Microwave Communication Equipment ODU, IDU, Dish, Antenna
The RF unit is an outdoor unit (ODU). The IF, signal processing, and MUX/DEMUX units are integrated in the indoor unit (IDU). The ODU and IDU areconnected through an IF cable.
The ODU can either be directly mounted onto the antenna or connected to the antenna through a short soft waveguide. Although the capacity is smaller than the trunk, due to the easy installation and maintenance, fast network construction, it's the most widely used microwave equipment.
SplitMount Microwave Equipment (2) Unit Functions Antenna: Focuses the RF signals transmitted by ODUs and increases the signal gain. ODU: RF processing, conversion of IF/RF signals. IF cable: Transmitting of IF signal, management signal and power supply of ODU. IDU: Performs access, dispatch, multiplex/demultiplex, and modulation/demodulation for services.
SplitMount Microwave Equipment – Installation
Microwave Antenna (1) http://www.daenotes.com/electronics/microwaveradar/digitalmicrowavecommunicationequipment
3/8
8/13/2015
Digital Microwave Communication Equipment ODU, IDU, Dish, Antenna
5
2 Tweet
Antennas are used to send and receive microwave signals. Parabolic antennas and cassegrainian antennas are two common types of microwave antennas. reddit Microwave antenna diameters includes: 0.3m, 0.6m, 1.2m, 1.8m,2.0m, 2.4m, 3.0m, 3.2metc. StumbleUpon Microwave Antenna (2) Submit submit
Email SHAREBAR
Different frequency channels in same frequency band can share one antenna.
Antenna Adjustment (1)
Antenna Adjustment (2) During antenna adjustment, change the direction vertically or horizontally. Meanwhile, use a multimeter to test the RSSI at the receiving end. Usually, the voltage wave will be displayed as shown in the lower right corner. The peak point of the voltage wave indicates the main lobe position in the vertical or horizontal direction. Largescope adjustment is unnecessary. Perform fine adjustment on the antenna to the peak voltage point. http://www.daenotes.com/electronics/microwaveradar/digitalmicrowavecommunicationequipment
4/8
8/13/2015
Digital Microwave Communication Equipment ODU, IDU, Dish, Antenna
When antennas are poorly aligned, a small voltage may be detected in one direction. In this case, perform coarse adjustment on the antennas at both ends, so that the antennas are roughly aligned. The antennas at both ends that are well aligned face a little bit upward. Though 1–2 dB is lost, reflection interference will be avoided.
Antenna Adjustment (3)
During antenna adjustment, the two wrong adjustment cases are show here. One antenna is aligned to another antenna through the side lobe. As a result, the RSSI cannot meet the requirements.
SplitMount Microwave Equipment – Antenna (1) Antenna gain Definition: Ratio of the input power of an isotropic antenna Pio to the input power of a parabolic antenna Pi when the electric field at a point is the same for the isotropic antenna and the parabolic antenna. Calculating formula of antenna gain:
G = Pio/Pi = (πD/λ)2 * η
Halfpower angle Usually, the given antenna specifications contain the gain in the largest radiation (main lobe) direction, denoted by dBi. The halfpower point, or the –3 dB point is the point which is deviated from the central line of the main lobe and where the power is decreased by half. The angle between the two halfpower points is called the halfpower angle. Calculating formula of halfpower angle: θ0.5 = (65o ~ 70o) λ/D http://www.daenotes.com/electronics/microwaveradar/digitalmicrowavecommunicationequipment
5/8
8/13/2015
Digital Microwave Communication Equipment ODU, IDU, Dish, Antenna
SplitMount Microwave Equipment – Antenna (2) Cross polarization discrimination Suppression ratio of the antenna receiving heteropolarizing waves, usually, larger than 30 dB. XdB＝10lgPo/Px Po: Receiving power of normal polarized wave Px: Receiving power of abnormal polarized wave
Antenna protection ratio ttenuation degree of the receiving capability in a direction of an antenna compared with that in A the main lobe direction. An antenna protection ratio of 180° is called fronttoback ratio.
SplitMount Microwave Equipment –ODU (1)
SplitMount Microwave Equipment –ODU (2) Specifications of Transmitter Working frequency band Generally, trunk radios use 6, 7, and 8 GHz frequency bands. 11, 13 GHz and higher frequency bands are used in the access layer (e.g. BTS access). Output power The power at the output port of a transmitter. Generally, the output power is 15 to 30 dBm.
SplitMount Microwave Equipment –ODU (3) Local frequency stability If the working frequency of the transmitter is unstable, the demodulated effectived signal ratio will be decreased and the bit error ratio will be increased. The value range of the local frequency stability is 3 to 10 ppm. Transmit Frequency Spectrum Frame The frequency spectrum of the transmitted signal must meet specified requirements, to avoid occupying too much bandwidth and thus causing too much interference to adjacent channels. The limitations to frequency spectrum iscalled transmit frequency spectrum frame.
SplitMount Microwave Equipment –ODU (4) Specifications of Receiver Working frequency band Receivers work together with transmitters. The receiving frequency on the local station is http://www.daenotes.com/electronics/microwaveradar/digitalmicrowavecommunicationequipment
6/8
8/13/2015
Digital Microwave Communication Equipment ODU, IDU, Dish, Antenna
the transmitting frequency of the same channel on the opposite station. Local frequency stability The same as that of transmitters: 3 to 10 ppm Noise figure The noise figure of digital microwave receivers is 2.5 dB to 5 dB.
SplitMount Microwave Equipment –ODU (5) assband P To effectively suppress interference and achieve the best transmission quality, the passband and amplitude frequency characteristics should be properly chosen. The receiver passband characteristics depend on the IF filter. Selectivity Ability of receivers of suppressing the various interferences outside the passband, especially the interference from adjacent channels, image interference and the interference between transmitted and received signals. Automatic gain control (AGC) range Automatic control of receiver gain. With this function, input RF signals change within a certain range and the IF signal level remains unchanges.
SplitMount Microwave Equipment –ODU (6)
SplitMount Microwave Equipment –IDU
Digital Microwave Communication Overview http://www.daenotes.com/electronics/microwaveradar/digitalmicrowavecommunicationequipment
7/8
8/13/2015
Digital Microwave Communication Equipment ODU, IDU, Dish, Antenna
‹ CO2 Laser (The molecular gas laser)
up
http://www.daenotes.com/electronics/microwaveradar/digitalmicrowavecommunicationequipment
Digital Microwave Communication Overview ›
8/8
