Abstract: To perform communication speedily and reliably at an increased frequency of communication occurrence when providing multiple antenna units which are set to the same frequency, each of antenna units having a gantry in a tollgate is set such that adjacent antenna units having the same frequency alternately perform communications. Each communication period is set to have a down link period in which an interrogation signal is transmitted and an up link period in which an unmodulated carrier wave is transmitted while a response signal is received. Upon receiving a signal, an on-vehicle device generates a response signal by using a control circuit and transmits the signal by reflection, and fixes a communication party for further communications. The communication cycles of adjacent antenna units are shifted from each other, thereby avoiding interference.

Abstract: The primary object of the invention is to realize a mobile object identification system of simple construction and low cost, in which the responding unit attached to a mobile object writes data only once when it receives write signals repeatedly in communication with antenna units. When a tag unit (responding unit) receives a write signal from a writing antenna unit, it writes data to the data memory when a completion flag is cleared. When the data is first written, a control circuit sets the completion flag. Then, if the tag unit receives additional write signals in the communication area of the same writing antenna unit, the control circuit invalidates the data write command on the ground that the completion flag is set, thereby preventing duplicate data writing.

Abstract: A high frequency filter for an electric instrument including a casing of metallic conductive material, an internal electric circuit element arranged within the casing, and a connector mounted on a peripheral wall of the casing for connecting the internal electric circuit element to an external electric circuit. The high frequency filter comprises an insulation substance layer arranged between the connector and a connection terminal of the circuit element, the insulation substance layer being made of a dielectric material whose dielectric constant decreases or increases in accordance with increase or decrease of wireless frequency applied thereto, and a pair of conductive layers formed on opposite surfaces of the insulation substance layer, one of the conductive layers being connected at one end thereof to the connector and at the other end thereof to the connection terminal of the circuit element, and the other conductive layer being connected to a portion of the casing.

Abstract: A high frequency wave absorbing ceramics can be used, for example, as an EMI preventive filter for interrupting high frequency waves intruding into electronic circuits. The high frequency wave absorbing ceramics are composed of a ternary composition comprising from 55 to 85 mol % of lead iron niobate Pb(Fe.sub.1/2 Nb.sub.1/2)O.sub.3, from 10 to 40 mol % of lead iron tungstate Pb(Fe.sub.2/3 W.sub.1/3)O.sub.3 and not more than 20 mol % of lead nickel tantalate Pb(Ni.sub.1/3 Ta.sub.2/3)O.sub.3 based on the total 100 mol % of a composition composed of lead iron niobate Pb(Fe.sub.1/2 Nb.sub.1/2)O.sub.3, lead iron tungstate Pb(Fe.sub.2/3 W.sub.1/3)O.sub.3 and lead nickel tantalate Pb(Ni.sub.1/3 Ta.sub.2/3)O.sub.3.

Abstract: A high frequency wave absorbing ceramics can be used, for example, as an EMI preventive filter for interrupting high frequency waves intruding into electronic circuits. The high frequency wave absorbing ceramics are composed of a ternary composition comprising from 50 to 80 mol % of lead iron niobate Pb(Fe.sub.1/2 Nb.sub.1/2)O.sub.3, from 10 to 40 mol % of lead iron tungstate Pb(Fe.sub.2/3 W.sub.1/3)O.sub.3 and not more than 40 mol % of lead iron tantalate Pb(Fe.sub.1/2 Ta.sub.1/2)O.sub.3 based on the total 100 mol % of a composition composed of lead iron niobate Pb(Fe.sub.1/2 Nb.sub.1/2)O.sub.3, lead iron tungstate Pb(Fe.sub.2/3 W.sub.1/3)O.sub.3 and lead iron tantalate Pb(Fe.sub.1/2 Ta.sub.1/2)O.sub.3.

Abstract: A high frequency wave absorbing ceramics can be used, for example, as an EMI preventive filter for interrupting high frequency wave intruding into electronic circuits. The high frequency wave absorbing ceramics are composed of a ternary composition comprising from 50 to 82.5 mol % of lead iron niobate Pb(Fe1/2Nb1/2)O.sub.3, from 17.5 to 40 mol % of lead iron tungstate Pb(Fe2/3W1/3)O.sub.3 and not more than 25 mole % of lead cobalt niobate Pb(Co1/3Nb2/3)O.sub.3 based on the total 100 mol % of a composition composed of lead iron niobate Pb(Fe1/2Nb1/2)O.sub.3, lead iron tungstate Pb(Fe2/3W1/3)O.sub.3 and lead cobalt niobate Pb(Co1/3Nb2/3)O.sub.3.

Abstract: A high frequency filter assembly for an electric instrument including an internal electric circuit element arranged within a casing of metallic conductive material, and a connector mounted on a peripheral wall of the casing for connecting an external electric circuit to the internal electric circuit element. The filter assembly comprises at least a pair of overlapped insulation thin plates to be arranged between the connector and a connection terminal of the circuit element, and an earth electrode strip disposed between the insulation thin plates and being connected to a portion of the casing.

Abstract: A high frequency filter in combination with an internal electronic circuit element of the flat-plate type, such as a hybrid integrated circuit element contained within a casing, includes an electrode member arranged on a circuit board within the casing to be grounded, an insulation substance layer, integrally formed on the electrode member and being made of a dielectric material whose dielectric constant decreases or increases in accordance with an increase or a decrease of wireless frequency applied thereto, and an electrode strip integrally formed on the insulation substance layer for connection to an external electric circuit. The internal electronic circuit element is integrally provided on either the electrode member or the insulation substance layer and connected to the electrode strip, and the electrode member is mounted on the circuit board to carry the electronic circuit element in place.

Abstract: A high frequency wave absorbing ceramics can be used, for example, as an EMI preventive filter for interrupting high frequency waves intruding into electronic circuits. The high frequency wave absorbing ceramics has a composition expressed by the chemical formula Pb{Fe.sub.1/2 Nb.sub.(1/2-x) Ta.sub.x }O.sub.3 where 0.1<x<0.35. The high frequency wave absorbing ceramics may be composed of a composition comprising from 30 to 80 mol % of lead iron niobate Pb(Fe.sub.1/2 Ta.sub.1/2)O.sub.3 based on the total 100 mol % of a Pb(Fe.sub.1/2 Nb.sub.1/2)O.sub.3 and from 20 to 70 mol % of lead iron tantalate composition composed of lead iron niobate Pb(Fe.sub.1/2 Nb.sub.1/2)O.sub.3 and lead iron tantalate Pb(Fe.sub.1/2 Ta.sub.1/2)O.sub.3.