求翻译：选频直放站，是将上、下行频率下变频为中频，进行选频限带处理后，再上变频恢复上、下行频率。是什么意思？

Selective Repeater is on the downlink frequency down-conversion to IF, the selected frequency band limited processing, upconversion to recovery on the downlink frequency.

Selected frequency has been placed on the site, is the line frequency, the frequency to downconvert A frequency-band after processing and then to the frequency, the recovery rate.

Chooses the frequency upending station, is the top and bottom line frequency under the frequency conversion is the intermediate frequency, after carries on chooses the frequency to limit belt processing, again on the frequency conversion restores the top and bottom line frequency.

Frequency selection repeaters, is down-converter to the uplink and downlink frequency-if, after frequency limit, then up recovery and downlink frequencies.

正在翻译，请等待...