| 摘要 |
A small elliptic high pass filter is incorporated into a low noise block downconverter (LNB) to reject image frequencies in a 12 GHz Direct home satellite television Broadcasting System (DBS). A waveguide transition with separate electric probes receives Ku-band satellite signals and transmits the signals to low noise amplifiers (LNAs), a power combiner, an elliptic high pass filter, and a HEMT MMIC receiver. Within the HEMT MMIC receiver, the signal is passed through an RF amplifier stage. A mixer mixes the signal from the RF amplifier stage with a local oscillator signal to produce an intermediate frequency (IF). An IF amplifier stage amplifies the IF signal which is further processed by a television decoder box. Due to the unique response of the elliptic high pass filter, the elliptic high pass filter provides a superior image rejection with lower insertion loss for the LNB, and therefore provides improved television reception quality.
|
