Patent ID: 7027775

Claim:
An automatic frequency-setting-method of wireless microphone-receivers, in the simultaneous use of a plurality of wireless microphones in the same area, for setting each of different frequencies to each of wireless microphones and microphone-receivers corresponding to each of the wireless microphones, respectively, said method comprising the steps of: (a) providing a control means having a function for setting a frequency in a demodulation means and a frequency table, in each of the microphone-receivers, wherein in the frequency table, a given range of frequencies is divided into groups and each of the groups includes frequencies that cause no radio wave interference such as the mutual modulation interference; (b) designating one specific microphone-receiver and the other microphone-receivers as a master microphone-receiver and slave microphone-receivers, respectively, and mutual-communicatably connecting each of the microphone-receivers by a connecting cable; (c) setting one frequency selected from a given group of the frequency table in the demodulation means of the master microphone-receiver; (d) sending an empty channel (frequency) information except the frequency set in the master microphone-receiver from the control means of the master microphone-receiver to the control means of a first slave microphone-receiver after the frequency of the master microphone-receiver being set; (e) after the empty channel-information is sent to the control means of the first slave microphone-receiver, the control means of the first slave microphone-receiver selects one of the remained frequencies from the given group with reference to the empty channel-information and sets the same in the demodulation means of the first slave microphone-receiver; and (f) sending the frequency information set in the first slave microphone-receiver to the control means of the master microphone-receiver; (g) next, the control means of the master microphone-receiver sends the empty channel-information renewed by excluding the frequency set in the first microphone-receiver, to a control means of the second slave microphone-receiver, whereby the control means of the second slave microphone-receiver selects one of the remained frequencies in the given group with reference to the empty channel-information and sets the same in the demodulation means of the second slave microphone-receiver, while the information of the frequency set in the second slave microphone-receiver is sent to the control means of the master microphone receiver; (h) thereby setting each of the frequencies up to the demodulation means of the final slave microphone-receiver N by repeating the sending of the empty channel-information excluding the frequencies set in the slave microphone-receivers to each of the slave microphone-receivers, setting the same in the each of the slave microphone-receivers with reference to the empty channel-information, and sending the channel-information set in each of the slave microphone-receiver to the master receiver.