| 摘要 |
FIELD: radio communication. SUBSTANCE: invention relates to communication equipment, in particular to portable sending-receiving radio stations o personal use. Receiver-transmitter includes receiving 1 and sending 2 sides, antenna 3 with antenna switch 4. Receiving side 1 incorporates preselector 5 connected to antenna 3 through antenna switch 4. Unit 6 preliminary frequency conversion is connected to output of preselector 5. Output of piezofilter 9 is connected to input of frequency mixer 10 to which second input heterodyne 11 is linked. Frequency detector 13 to which there are connected noise suppressor 14 and low frequency amplifier 15 is linked via piezofilter 12 to output of mixer 10. Dynamic head 16 is connected to output of amplifier 15. Sending side 2 is composed of frequency modulator 17 to which input microphone 18 is linked. Frequency modulator is connected to generator 19 controlled by voltage and embraced by ring of phase automatic adjustment of frequency which is realized in following way: output of generator 19 controlled by voltage is connected to one of inputs of comparator 20. Output of reference generator 21 is connected to other input of comparator 20. Output of comparator 20 is connected to counting input of counter-divider 22, channel control unit 23 is connected to input of setting of scaling ratio of counter-divider 22. Input of pulse-frequency phase detector 24 is linked to output of counter-divider 24. Output of clock pulse generator 25 is connected to other input of phase detector. Output of pulse-frequency phase detector 24 is connected to generator 19 controlled by voltage via integrating circuit 26. In addition output of generator 19 controlled by voltage is linked to inputs of frequency mixers 7 of receiving side and 27 of sending side. Quartz generator 28 is connected to second input of frequency mixer 27. Input of high-frequency amplifier 30 is connected to output of mixer 27 via LC filter 29. Antenna 3 and antenna switch 4 are linked to output of high-frequency amplifier 30 via low-frequency filter 31 and indicator of output power of transmitter 32. EFFECT: improved quality of reception, increased communication range, possibility for user of selection of available communication channel. 2 dwg |
