Modulating and demodulating device

• US 6,176,432 B1
• Filed: 02/19/1999
• Issued: 01/23/2001
• Est. Priority Date: 03/09/1998
• Status: Expired due to Fees

• Current Assignee: ALPS Electric Company Limited (Alps Alpine Co., Ltd.)
• Original Assignee: ALPS Electric Company Limited (Alps Alpine Co., Ltd.)
• Inventors: Miyaura, Masao
• Primary Examiner(s): Frech, Karl D.
• Application Number:
  US09/253,444
• Time in Patent Office: 704 Days
• Field of Search: 235/492, 235/487, 235/375, 235/380, 235/493, 235/491, 235/384, 455/126
• US Class Current: 235/487
• CPC Class Codes: G06K 19/0723 the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
• CPC Class Codes: G07B 15/063 using wireless information transmission between the vehicle and a fixed station identification of vehicles G08G
• CPC Class Codes: H03C 7/027 using diodes
• CPC Class Codes: H04L 27/04 Modulator circuits; Transmitter circuits
• CPC Class Codes: H04L 27/06 Demodulator circuits; Receiver circuits

Abstract

The modulating and demodulating device comprises a microstrip line network connected to a transmitting/receiving antenna, the modulator-demodulator having first and second diodes connected to an output of the microstrip line network, and a bias voltage supplying circuit for supplying a bias voltage selectively to the first and second diodes. In the modulator-demodulator, the first diode is connected between the input and output terminals, and the second diode is connected between the input terminal and a reference potential point. When the modulator-demodulator executes a modulating operation, the bias voltage supplying circuit supplies a bias voltage to turn on both the first and second diodes or a bias voltage to turn on only the first diode in accordance with a modulation signal. When the modulator-demodulator executes a demodulating operation, the bias voltage supplying circuit supplies a bias voltage to turn off both the first and second diodes.

Claims

1. A modulating and demodulating device comprising:

a mirostrip line network connected to a transmitting/receiving antenna, a modulator-demodulator having a first diode and a second diode which are connected to an output of the microstrip line network, and a bias voltage supplying circuit for supplying a bias voltage selectively to the first diode and the second diode,

wherein, in the modulator-demodulator, the first diode is serially connected between input and output terminals and the second diode is shunt-connected between the input terminal and a reference potential point, when the modulator-demodulator executes a modulating operation, the bias voltage supplying circuit supplies a bias voltage to turn on both the first and second diodes or a bias voltage to turn on only the first diode in accordance with a modulation signal, and when the modulator-demodulator performs a demodulating operation, the bias voltage supplying circuit supplies a bias voltage to turn off both the first and second diodes.

2. A modulating and demodulating device according to claim 1, wherein the modulating and demodulating device is used for an on-vehicle transmitter-receiver in an automatic toll collecting system.