Low power, low out-of-band harmonic content radio
A radio that includes a transceiver to transmit and receive RF signals. The transceiver including a transmitter, a transformer, and a receiver, the transformer is coupled to and shared between the transmitter and the receiver. A resonator is formed by the combination of the transformer and capacitive elements of the transmitter and receiver.
1. A radio comprising:
a transmitter including:
a voltage controlled oscillator (VCO);
a first amplifier stage coupled to the VCO and having a differential output;
a transformer having first and second inductors, the first inductor being directly coupled to the differential output of the first amplifier stage; and
a second amplifier stage having a single-ended input directly coupled to the second inductor of the transformer,
wherein a resonator is formed by the combination of the transformer and capacitive elements of the transmitter.
2. The radio of claim 1 , wherein the transmitter further includes a third amplifier stage having a single-ended input coupled to a single-ended output of the second amplifier stage.
3. The radio of claim 1 , wherein the transformer is configured to convert a differential output signal produced by the first amplifier stage to a single-ended signal.
4. The radio of claim 1 , further comprising:
a receiver including:
an amplifier; and
a mixer,
wherein the transformer is coupled between the amplifier of the receiver and the mixer of the receiver.
5. The radio of claim 4 , wherein the transformer includes a center tap, and wherein a different voltage is applied to the center tap of the transformer during transmission than during reception.
6. The radio of claim 1 , wherein the transmitter is constructed on a single integrated circuit.
7. A device comprising:
a transmitter including:
a first amplifier stage having a differential output;
a second amplifier stage having a single-ended input; and
a transformer coupled to the differential output of the first amplifier stage and to the single-ended input of the second amplifier stage,
wherein the transformer includes a first inductor directly coupled to the differential output of the first amplifier stage, and a second inductor directly coupled to the single-ended input of the second amplifier stage, and
wherein a resonator is formed by the combination of the transformer and capacitive elements of the transmitter.
8. The device of claim 7 , wherein the transmitter further includes a third amplifier stage having a single-ended input coupled to a single-ended output of the second amplifier stage.
9. The device of claim 7 , wherein the transformer is configured to convert a differential output signal produced by the first amplifier stage to a single-ended signal.
10. The device of claim 7 , further comprising:
a receiver including:
an amplifier; and
a mixer,
wherein the transformer is coupled between the amplifier of the receiver and the mixer of the receiver.
11. The device of claim 10 , wherein the transformer includes a center tap, and wherein a different voltage is applied to the center tap of the transformer during transmission than during reception.
12. The device of claim 7 , wherein the transmitter is constructed on a single integrated circuit.
13. An integrated circuit comprising:
a transmitter including:
a first amplifier stage having a differential output;
a second amplifier stage having a single-ended input; and
a transformer coupled to the differential output of the first amplifier stage and to the single-ended input of the second amplifier stage,
wherein the transformer includes a first inductor directly coupled to the differential output of the first amplifier stage, and a second inductor directly coupled to the single-ended input of the second amplifier stage, and
wherein a resonator is formed by the combination of the transformer and capacitive elements of the transmitter.
14. The integrated circuit of claim 13 , wherein the transmitter further includes a third amplifier stage having a single-ended input coupled to a single-ended output of the second amplifier stage.
15. The integrated circuit of claim 13 , wherein the transformer is configured to convert a differential output signal produced by the first amplifier stage to a single-ended signal.
16. The integrated circuit of claim 13 , further comprising:
a receiver including:
an amplifier; and
a mixer,
wherein the transformer is coupled between the amplifier of the receiver and the mixer of the receiver.
17. The integrated circuit of claim 16 , wherein the transformer includes a center tap, and wherein a different voltage is applied to the center tap of the transformer during transmission than during reception.