Radio transmission apparatus
A radio transmission apparatus includes a radio transmission IC including a vibration element and a fractional N-PLL circuit and a power amplifier generating a radio transmission signal and a control device that controls the radio transmission IC, and a temperature detection element. The control device controls the fractional N-PLL circuit based on temperature information obtained from the temperature detection element such that a frequency of the radio transmission signal is temperature-compensated.
1. A radio transmission apparatus comprising:
a vibration element;
a radio transmission semiconductor device that includes a fractional N-PLL circuit generating a radio transmission clock signal based on an output signal of the vibration element and a power amplifier generating a radio transmission signal based on the radio transmission clock signal;
a control device that is configured to control the radio transmission semiconductor device; and
a temperature detection element that is connected to the control device,
wherein the control device is configured to control the fractional N-PLL circuit based on temperature information obtained from the temperature detection element such that a frequency of the radio transmission signal is temperature-compensated.
2. The radio transmission apparatus according to claim 1 ,
wherein the temperature detection element is a thermistor that detects temperature of the vibration element.
3. The radio transmission apparatus according to claim 2 ,
wherein the control device outputs a division set signal that is configured to set a division ratio of the fractional N-PLL circuit based on the temperature information.
4. The radio transmission apparatus according to claim 2 ,
wherein the radio transmission semiconductor device includes a logic circuit and a plurality of registers,
the logic circuit is configured to calculate a division ratio of the fractional N-PLL circuit based on setting values of the plurality of registers so that the logic circuit is configured to perform delta-sigma modulation to cause the fractional N-PLL circuit to generate the radio transmission clock signal.
5. The radio transmission apparatus according to claim 1 ,
wherein the vibration element is an AT cut quartz crystal vibration element.
6. The radio transmission apparatus according to claim 1 ,
wherein the radio transmission semiconductor device and the vibration element are accommodated in one package.
7. The radio transmission apparatus according to claim 1 ,
wherein the temperature detection element and the vibration element are accommodated in one package.
8. The radio transmission apparatus according to claim 1 ,
wherein the control device outputs a division set signal that is configured to set a division ratio of the fractional N-PLL circuit based on the temperature information.
9. The radio transmission apparatus according to claim 8 ,
wherein the control device is configured to maintain a calculation formula or table information indicating a relation between an output voltage and the temperature of the temperature detection element.
10. The radio transmission apparatus according to claim 8 ,
wherein the fractional N-PLL circuit is configured to generate the radio transmission clock signal having a frequency F PLL , and
wherein the control device is configured to maintain frequency-temperature characteristic information of the vibration element so as to calculate a frequency F REF of the vibration element based on the temperature information and to calculate an integer division ratio N and a fraction division ratio F/M based on:
F
PLL
=
(
N
+
F
M
)
×
F
REF
.
11. The radio transmission apparatus according to claim 6 ,
wherein the radio transmission semiconductor device is configured to perform frequency shift keying modulation and amplitude shift keying modulation with respect to the radio transmission signal based on a control signal from the control device.
12. The radio transmission apparatus according to claim 1 ,
wherein the radio transmission semiconductor device includes a logic circuit and a plurality of registers,
the logic circuit is configured to calculate a division ratio of the fractional N-PLL circuit based on setting values of the plurality of registers so that the logic circuit is configured to perform delta-sigma modulation to cause the fractional N-PLL circuit to generate the radio transmission clock signal.
13. The radio transmission apparatus according to claim 12 ,
wherein the control device is configured to maintain a calculation formula or table information indicating a relation between an output voltage and the temperature of the temperature detection element.
14. The radio transmission apparatus according to claim 12 ,
wherein the fractional N-PLL circuit is configured to generate the radio transmission clock signal having a frequency F PLL , and
wherein the control device is configured to maintain frequency-temperature characteristic information of the vibration element so as to calculate a frequency F REF of the vibration element based on the temperature information and to calculate an integer division ratio N and a fraction division ratio F/M based on:
F
PLL
=
(
N
+
F
M
)
×
F
REF
.
15. The radio transmission apparatus according to claim 12 ,
wherein the radio transmission semiconductor device is configured to perform frequency shift keying modulation and amplitude shift keying modulation with respect to the radio transmission signal based on a control signal from the control device.
16. The radio transmission apparatus according to claim 1 ,
wherein the control device is configured to maintain a calculation formula or table information indicating a relation between an output voltage and the temperature of the temperature detection element.
17. The radio transmission apparatus according to claim 16 ,
wherein the fractional N-PLL circuit is configured to generate the radio transmission clock signal having a frequency F PLL , and
wherein the control device is configured to maintain frequency-temperature characteristic information of the vibration element so as to calculate a frequency F REF of the vibration element based on the temperature information and to calculate an integer division ratio N and a fraction division ratio F/M based on:
F
PLL
=
(
N
+
F
M
)
×
F
REF
.
18. The radio transmission apparatus according to claim 1 ,
wherein the fractional N-PLL circuit is configured to generate the radio transmission clock signal having a frequency F PLL , and
wherein the control device is configured to maintain frequency-temperature characteristic information of the vibration element so as to calculate a frequency F REF of the vibration element based on the temperature information and to calculate an integer division ratio N and a fraction division ratio F/M based on:
F
PLL
=
(
N
+
F
M
)
×
F
REF
.
19. The radio transmission apparatus according to claim 18 ,
wherein the radio transmission semiconductor device is configured to perform frequency shift keying modulation and amplitude shift keying modulation with respect to the radio transmission signal based on a control signal from the control device.
20. The radio transmission apparatus according to claim 1 ,
wherein the radio transmission semiconductor device is configured to perform frequency shift keying modulation and amplitude shift keying modulation with respect to the radio transmission signal based on a control signal from the control device.