ASK modulator and transmitter having the same
A modulator which has a first terminal to receive a carrier signal, a second terminal to receive a first control signal to control a frequency band of the carrier signal and a third terminal to receive a second control signal to control a modulation depth of the carrier signal.
1. A modulator comprising:
a first terminal to receive a carrier signal;
a second terminal to receive a first control signal to control an ASK modulation of the carrier signal;
a third terminal to receive a second control signal to control an ASK modulation depth of the carrier signal; and
a PIN diode for signal modulation.
2. The modulator of claim 1 , wherein the second terminal and the third terminal are connected to a control unit.
3. The modulator of claim 1 , wherein the third terminal is connected to a direct current (DC) voltage source.
4. The modulator of claim 2 , wherein the modulator further comprises a carrier generator and an amplification circuit connected between the carrier generator and the first terminal of the modulator, wherein the modulator has a fourth terminal connected to an antenna.
5. The modulator of claim 4 , wherein the modulator comprises:
a variable resistor being provided with a voltage level;
a switch connected in series to the variable resistor and electrically coupled to the second terminal of the modulator;
a first resistor connected in parallel to the switch;
a second resistor connected in series to the first resistor;
a first inductor having a first terminal connected to the second resistor and a second terminal to an output of the amplification circuit;
the PIN diode having an anode connected to the output of the amplification circuit and the second terminal of the first inductor and an cathode connected to the antenna; and
a second inductor having a first terminal connected to the cathode of the PIN diode and a second terminal, wherein the second terminal is grounded.
6. The modulator of claim 5 further comprises a transistor having a first terminal connected to the third terminal of the modulator, a second terminal and a third terminal, wherein the second resistor is connected between the second and third terminals of the transistor.
7. The modulator of claim 6 , wherein the transistor is a metal-oxide-semiconductor (MOS) transistor.
8. The modulator of claim 2 , wherein the modulator further comprises a carrier generator and an amplification circuit connected between the carrier generator and the first terminal of the modulator, wherein the modulator has a fourth terminal connected to an antenna and the amplification circuit comprises a buffer amplifier.
9. The modulator of claim 8 , wherein the amplification circuit comprises a power amplifier in series connection to the buffer amplifier.
10. A transmitter comprising:
a carrier generator for generating a carrier signal;
an amplification circuit having an input terminal connected to the carrier generator;
a modulator having a first terminal connected to an output of the amplification circuit; and
an antenna having an input connected to the modulator,
wherein the modulator comprises a second terminal to receive a first control signal to control an ASK modulation of the carrier signal; and
wherein the modulator comprises a PIN diode for signal modulation, and
wherein the modulator comprises a third terminal to receive a second control signal to control a modulation depth of the carrier signal.
11. The transmitter of claim 10 , wherein the modulator comprises the third terminal connected to a direct current (DC) voltage source, the DC voltage source supplies a voltage level to the third terminal of the modulator to control the modulation depth of the carrier signal.
12. The transmitter of claim 10 , wherein the modulator comprises:
a variable resistor being provided with a voltage level;
a switch connected in series to the variable resistor and electrically coupled to the second terminal of the modulator;
a first resistor connected in parallel to the switch;
a second resistor connected in series to the first resistor;
a first inductor having a first terminal connected to the second resistor and a second terminal to the output of the amplification circuit;
the PIN diode having an anode connected to the output of the amplification circuit and the second terminal of the first inductor and an cathode connected to the antenna; and
a second inductor having a first terminal connected to the cathode of the PIN diode and a second terminal, wherein the second terminal is grounded.
13. A modulator comprising:
a variable resistor being provided with a voltage level;
a switch connected in series to the variable resistor;
a first resistor connected in parallel to the switch;
a second resistor connected in series to the first resistor;
a first inductor having a first terminal connected to the second resistor and a second terminal to receive a carrier signal;
a PIN diode having an anode connected to the second terminal of the first inductor and an cathode to output a modulated signal; and
a second inductor having a first terminal connected to the cathode of the PIN diode and a second terminal, wherein the second terminal is grounded,
wherein the switch receives a first control signal to control an ASK modulation of the carrier signal.
14. The modulator of claim 13 , wherein the modulator further comprises a transistor having a first terminal, a second terminal and a third terminal, wherein the second resistor is connected between the second and third terminals.
15. The modulator of claim 14 , wherein the first terminal of the transistor receives a second control signal to control a modulation depth of the carrier signal.
16. The modulator of claim 13 , wherein the anode of the PIN diode and the second terminal of the first inductor are connected to an output of a power amplifier.
17. The modulator of claim 13 , wherein the cathode of the PIN diode is connected to an antenna.