Low power consumption binary phase-shift-keyed (BPSK) modulator using reflective electronic switching techniques

• US 5,455,544 A
• Filed: 01/28/1994
• Issued: 10/03/1995
• Est. Priority Date: 01/28/1994
• Status: Expired due to Term

• Current Assignee: Thomson Consumer Electronics Incorporated (Vantiva SA)
• Original Assignee: Thomson Consumer Electronics Incorporated (Vantiva SA)
• Inventors: Kechkaylo, David L.
• Primary Examiner(s): Pascal, Robert J.
• Assistant Examiner(s): KINKEAD, ARNOLD M
• Application Number:
  US08/188,967
• Time in Patent Office: 613 Days
• Field of Search: 332/103, 332/104, 332/105, 375/52-55, 375/67, 375/83, 375/86, 375/87, 375/17, 375/279, 375/280, 375/281, 375/282, 375/308, 375/329, 375/332, 375/333, 375/200
• US Class Current: 332/103
• CPC Class Codes: H04L 27/2057 with a separate carrier for each phase state

Abstract

A low power consumption BPSK modulator uses only a single input transformer which is not required to be center-tapped, and a switching arrangement including four junction field effect transistors. An advantage of the subject invention is that the DC switching current is reduced by a factor of approximately 1500 with respect to a conventional diode ring modulator. The carrier signal loss of the subject apparatus is lower than that exhibited by a ring modulator due to the use of only a single transformer, and due to the low on-resistance of the JFETs. An extremely important advantage of the subject invention in the field of cordless telephone handsets is that the subject apparatus can be made relatively small due to the necessity for only one transformer.

Claims

1. A low power consumption biphase modulator, comprising:

an input terminal for receiving an input RF signal of a predetermined phase;

an output terminal for developing an RF signal in phase with respect to said input RF signal or substantially 180-degrees out of phase with respect to said input RF signal;

a non-tapped transformer having a primary winding coupled to said input terminal for receiving said input RF signal, and having a secondary winding including first and second ends for developing at opposite ones of said first and second ends said in-phase and out-of-phase RF signals; and

a switch array exhibiting first and second states in response to a control signal, in said first state said switch array couples said first end of said secondary winding to said output terminal for developing said in-phase RF signal and couples said second end of said secondary winding to a source of reference potential without substantial intervening impedance and in said second state, said switch array couples said second end of said secondary winding to said output terminal for developing said out-of-phase signal and couples said first end of said secondary winding to a source of reference potential without substantial intervening impedance;

said switch array having a control terminal for receiving said control signal for controlling which of said in-phase and out-of-phase RF signal is selected;

said biphase modulator including no transformer other than said non-tapped transformer.

2. A low power consumption biphase modulator, comprising:

an input terminal for receiving an input RF signal of a predetermined phase;

an output terminal for developing an RF signal in phase with respect to said input RF signal or substantially 180-degrees out of phase with respect to said input RF signal;

a non-tapped transformer having a primary winding coupled to said input terminal for receiving said input RF signal, and having a secondary winding including first and second ends for developing at opposite ones of said first and second ends said in-phase and out-of-phase RF signals; and

an FET switch array exhibiting first and second states in response to a control signal, in said first state said FET switch array couples said first end of said secondary winding to said output terminal for developing said in-phase RF signal and couples said second end of said secondary winding to a source of reference potential without substantial intervening impedance, and in said second state, said FET switch array couples said second end of said secondary winding to said output terminal for developing said out-of-phase signal and couples said first end of said secondary winding to a source of reference potential without substantial intervening impedance;

said FET switch array having said control terminal for receiving a control signal for controlling which of said in-phase and out-of-phase RF signals is selected;

said biphase modulator including no transformer other than said non-tapped transformer.

3. The low power consumption biphase modulator of claim 2 wherein,

said FET switch array is a GaAs JFET array.

4. The low power consumption biphase modulator of claim 2 wherein,

said FET switch array is a MOSFET array.

5. A low power consumption biphase modulator, comprising:

an input terminal for receiving an input RF signal of a predetermined phase;

an output terminal for developing an RF signal in phase with respect to said input RF signal or substantially 180-degrees out of phase with respect to said input RF signal;

a non-tapped transformer having a primary winding coupled to said input terminal for receiving said input RF signal, and having first and second ends of a secondary winding for developing at opposite ones of said first and second ends said in-phase and out-of-phase RF signals;

first and second capacitors coupled to said first and second ends of said secondary winding of said transformer for coupling said RF signal but blocking a DC signal; and

an FET switch array exhibiting first and second states in response to a control signal, in said first state said FET switch array couples said first end of said secondary winding to said output terminal via a third capacitor for developing said in-phase RF signal and couples said second end of said secondary winding to a source of reference potential via a fourth capacitor without substantial intervening impedance and in said second state, said FET switch array couples said second end of said secondary winding to said output terminal via said fourth capacitor for developing said out-of-phase signal and couples said first end of said secondary winding to a source of reference potential via said third capacitor without substantial intervening impedance;

said FET switch array having a control terminal for receiving said control signal for controlling which of said in-phase and out-of-phase RF signal is selected;

said biphase modulator including no transformer other than said non-tapped transformer.

6. A low power consumption biphase modulator, comprising:

an input terminal for receiving an input RF signal of a predetermined phase;

an output terminal for developing an RF signal in phase with respect to said input RF signal or substantially 180-degrees out of phase with respect to said input RF signal;

an input transformer having a primary winding coupled to said input terminal for receiving said input RF signal, and having first and second ends of a secondary winding for developing at opposite ones of said first and second ends said in-phase and out-of-phase RF signals; and

a switch array exhibiting first and second states in response to a control signal, in said first state said switch array couples said first end of said secondary winding to said output terminal for developing said in-phase RF signal and couples said second end of said secondary winding to a source of reference potential without substantial intervening impedance and in said second state, said switch array couples said second end of said secondary winding to said output terminal for developing said out-of-phase signal and couples said first end of said secondary winding to a source of reference potential without substantial intervening impedance;

said switch array having a control terminal for receiving said control signal for controlling which of said in-phase and out-of-phase RF signal is selected;

said biphase modulator including no transformer other than said input transformer.

7. In direct sequence spread spectrum battery-powered communications equipment, a low power consumption biphase modulator, comprising:

an input terminal for receiving a 900 MHz input RF carrier signal of a predetermined phase;

an output terminal for developing an RF signal in phase with respect to said input RF signal or substantially 180-degrees out of phase with respect to said input RF signal;

a non-tapped transformer having a primary winding coupled to said input terminal for receiving said 900 MHz input RF carrier signal, and having a secondary winding including first and second ends for developing at opposite ones of said first and second ends said in-phase and out-of-phase RF carrier signals; and

an FET switch array exhibiting first and second states in response to a control signal, in said first state said FET switch array couples said first end of said secondary winding to said output terminal for developing said in-phase RF signal and couples said second end of said secondary winding to a source of reference potential without substantial intervening impedance, and in said second state, said FET switch array couples said second end of said secondary winding to said output terminal for developing said out-of-phase signal and couples said first end of said secondary winding to a source of reference potential without substantial intervening impedance;

said FET switch array having a control terminal for receiving said control signal for controlling which of said in-phase or out-of-phase carrier signals is selected, said control signal being a combination of a binary representation of speech and a spreading code;

said biphase modulator including no transformer other than said non-tapped transformer.

8. The low power consumption biphase modulator of claim 7 wherein,

said FET switch array is a GaAs JFET array.

9. The low power consumption biphase modulator of claim 7 wherein,

said FET switch array is a MOSFET array.

10. A low power consumption quadraphase modulator, comprising:

an input terminal for receiving an input RF signal of a predetermined phase;

an output terminal for developing an RF signal which is one of in phase with respect to said input RF signal, 90-degrees out-of-phase with respect to said input RF signal, 180-degrees out-of-phase with respect to said input RF signal, and 270-degrees out-of-phase with respect to said input RF signal;

a quadrature phase network for developing first and second RF signals having a 90-degree phase shift between them;

a first non-tapped transformer having a primary winding coupled to said input terminal for receiving said input RF signal, and having a secondary winding including first and second ends for developing at opposite ones of said first and second ends said in-phase and said 180-degree-out-of-phase RF signals; and

a second non-tapped transformer having a primary winding coupled to said quadrature phase network for receiving said RF signal having a 90-degree phase shift with respect to said input RF signal, and having a secondary winding including first and second ends for developing at opposite ones of said first and second ends said 90-degree out-of-phase and 270-degree out-of-phase RF signals; and

a first switch array exhibiting first and second states in response to a first control signal, in said first state said first switch array couples said first end of said secondary winding of said first transformer to said output terminal for developing said in-phase RF signal and couples said second end of said secondary winding of said first transformer to a source of reference potential without substantial intervening impedance, and in said second state said first switch array couples said second end of said secondary winding of said first transformer to said output terminal for developing said 180-degree-out-of-phase signal and couples said first end of said secondary winding of said first transformer to a source of reference potential without substantial intervening impedance;

a second switch array exhibiting third and fourth states in response to a second control signal, in said third state said second switch array couples said first end of said secondary winding of said second transformer to said output terminal for developing said 90-degree out-of-phase RF signal and couples said second end of said secondary winding of said second transformer to a source of reference potential without substantial intervening impedance, and in said fourth state said secondary switch array couples said second end of said secondary winding of said second transformer to said output terminal for developing said 270-degree-out-of-phase signal and couples said first end of said secondary winding of said second transformer to it source of reference potential without substantial intervening impedance;

each of said first and second switch arrays having a control terminal for receiving a respective one of said first and second control signals for controlling which of said phases of said RF signal is selected;

said biphase modulator including no output transformer.