频率谐波

In the above video, the left side is our FDD two-frequency COFDM transceiver module. At the center of the metal box, there is the filter. 在视频中, we will show you the test of the COFDM Video transmitter output with filters and without 过滤器.

Now It is directly connected to the antenna without a filter. We will see the frequency harmonics generated by the transmitter.

在视频中, the highest wave is the current transmitting frequency.
The second highest is the second harmonic, The third highest is the third harmonic, and the lowest wave is the fourth harmonic. No more frequency harmonics after this.

It can be seen from the current test equipment that if there is no filter, the transmitter will produce frequency harmonics. Harmonics occur at frequencies 2 时, 3 时, 和 4 times the frequency. Frequency harmonics can cause interference with other equipment.

Now let’s look at adding a filter to the output of the transmitter to see if there are still frequency harmonics.

Connect a filter between the transmitter and the antenna. This is a 340Mhz wavepass filter. Between frequencies of 330Mhz and 350Mhz signals can pass, and other signals are blocked. In our 1886 dual-frequency video transceiver, you can choose two frequencies, one for uplink and one for downlink.

Transmitting and receiving are performed at two frequencies respectively, which increases the transmission rate and anti-interference performance.

Now the filter is connected from the transmitter to the antenna. Now there are no frequency harmonics on the screen. Except for the transmission frequency, all other clutter has been filtered out.

Now you know the important role of filters. If you need to customize a COFDM transmitter, PA, or filter, please contact us for free solutions and quotations. ivcan.com/contact