S meter

Abstract: PROBLEM TO BE SOLVED: To reduce adverse influences upon other communication equipments existent in the same area and to reduce the influences of sensitivity suppression or mutual modulation by varying the signal level of at least one of reception and transmission signals through a signal level varying means based on the output level of a reception level detecting circuit giving an output corresponding to a reception level SOLUTION: This radio data communication equipment is provided with first and second attenuators 8 and 9 for respectively attenuating the levels of a reception signal giving from an antenna 7 to a reception circuit 1 and a transmission signal outputted from a transmission circuit 6 to the antenna 7 based on the output level of an S meter as the reception level detecting circuit giving the output corresponding to the reception level When the output level of the S meter is higher than a fixed level, namely, when there is a sufficient reception input, an MPU 4 attenuates the levels of the reception and transmission signals through the first and second attenuators 8 and 9 corresponding to the output level of the S meter

Abstract: A signal strength meter circuit for an FM radio receiver employing automatic gain control. The signal strength meter circuit includes circuitry for establishing a range of voltages on an AGC line of the receiver corresponding to a range of signals received by the receiver and for providing deflection of a needle of a signal strength meter over the entire range. At such time as AGC circuitry in the receiver draws current from the meter circuit, the meter continues to display this current by the deflection of the needle of the meter.

Abstract: PROBLEM TO BE SOLVED: To maintain receiving signal quality excellent even while signal suppression is being incurred by an interference signal. SOLUTION: An in-vehicle broadcast receiver 1 comprises a tuning circuit 3, a tuner circuit 4 connected to the tuning circuit 3 and a demodulation circuit 13 for demodulating a signal outputted by the tuner circuit 4. In this in-vehicle broadcast receiver 1, a control section 20 is provided which changes a tuning property of the tuning circuit 3 at the interval of predetermined steps. Each time the tuning property is changed by the predetermined steps, the control section 20 acquires an S meter signal Sm indicating a reception field strength and a noise signal Ns indicating whether noise contained in the signal demodulated by the demodulation circuit 13 is much or a little, and is configured to specify a tuning property of high reception field strength and a little noise on the basis of the S meter signal Sm and the noise signal Ns in the predetermined steps of the tuning property and to set the specified tuning property to the tuning circuit 3. COPYRIGHT: (C)2009,JPO&INPIT