Pole switch down converter with symmetric resonator

• US 20050255820A1
• Filed: 05/09/2005
• Published: 11/17/2005
• Est. Priority Date: 05/11/2004
• Status: Active Grant

• Current Assignee: Sony Deutschland GmbH (Sony Group Corp.)
• Original Assignee: Sony Deutschland GmbH (Sony Group Corp.)
• Inventors: Ruhm, Ingo, Bohnke, Ralf
• Granted Patent: US 7,184,725 B2
• Time in Patent Office: Days
• US Class Current: 455/313
• CPC Class Codes: H04B 1/24 the receiver comprising at least one semiconductor device having three or more electrodes

Abstract

A pole switch down-converter with symmetric resonator which reduce the non resonating phase to approximately half of the RF carrier period of the modulated signal is proposed. The down-converter comprises a first and second λ/2 resonator for collecting RF energy, wherein a differential RF signal is coupled to the first and second λ/2 resonator, a switching means coupled at one end of the first λ/2 resonator and one end of second λ/2 resonator for connecting the first and second λ/2 resonator, a control means for controlling the switching means, and a detecting means coupled to the first and second λ/2 resonator for detecting the down-converted signal, wherein the control means is adapted to initiate in a down-conversion cycle the switching means to connect the first and second λ/2 resonator for approximate half of the RF carrier period of the modulated signal. With this pole switch down-converter adjacent RF channels can be selected and down-converted by slightly varying the pole switch repetition rate.

Claims

1. A circuit for down-converting a modulated signal comprising:

a first and second λ

/2 resonator for collecting RF energy, wherein a differential RF signal is coupled to said first and second λ

/2 resonator;

a switching means coupled at one end of the first λ

/2 resonator and one end of second λ

/2 resonator for connecting said first and second λ

/2 resonator;

a control means for controlling said switching means; and

a detecting means coupled to said first and second λ

/2 resonator for detecting the down-converted signal, wherein

said control means is adapted to initiate in a down-conversion cycle of said switching means to connect said first and second λ

/2 resonator for approximate half of the RF carrier period of the modulated signal.

2. A circuit according claim 1, wherein

said control means is adapted to initiate said detecting means to detect the down-converted signal after said switching means is switched off.

3. A circuit according claim 1, wherein

said switching means is a FET transistor.

4. A circuit according to claim 1, wherein

said detecting means is a differential amplifier.

5. A circuit according to claim 1, further comprising

a means for generating the differential RF signal coupled to said first and second λ

/2 resonator.

6. A circuit according to claim 1, wherein

said first and second λ

/2 resonator is a micro-strip transmission line with open end or equivalently open for the RF signal.

7. A circuit according to claims 1, wherein

said first and second λ

/2 resonator is a micro-strip transmission line with shortened end or equivalently shortened end for the RF signal.

8. A circuit according to claim 1, wherein

said first and second λ

/2 resonator is an electronic circuit providing a delay at the feeding point equivalent to one wavelength λ

.

9. A circuit according to claim 1, wherein

said first and second λ

/2 resonator is each one arm of a dipole antenna.

10. A circuit according to claim 1, wherein

for selecting a predetermined modulated signal from a plurality of adjacent RF channels said control means is adapted to initiate said switching means to change the switch rate according to

$f_{\mathrm{IF}}=\{\begin{array}{c}\mathrm{frac}\end{array}$

(fRFfp)·

fpfrac⁡

(fRFfp)<

0.5(1-frac⁡

(fRFfp))·

fpelse

wherein,

f_IF is intermediate frequency of the down-converted signal,

f_RF centre frequency of the RF channel,

f_p is the switch rate, and

frac(x) is the fractional part of the argument x.

11. A circuit according to claim 6, wherein

said detecting means comprises a bandpass filter for filtering intermediate frequency signal.

12. A method for down-converting a modulated signal, comprising the steps of:

providing a first and second λ

/2 resonator for collecting RF energy,

coupling a differential RF signal to said first and second λ

/2 resonator;

connecting after said first and second λ

/2 resonator oscillate, said first and second λ

/2 resonator for approximate half of the RF carrier period of the modulated signal; and

detecting the down-converted signal.

13. A method according claim 12, wherein

the down-converted signal is detected after said first and second λ

/2 resonator are disconnected.

14. A method according to claim 12 wherein

in said detecting step a differential signal at the ends at which said first and second λ

/2 resonator are connected is detected.

15. A method according to claim 12, further comprising the step of

generating the differential RF signal which is coupled to said first and second λ

/2 resonator.

16. A method according to claim 12, wherein

said first and second λ

/2 resonator is a micro-strip transmission line with open end or equivalently open for the RF signal.

17. A method according to claim 12, wherein

said first and second λ

/2 resonator is a micro-strip transmission line with shortened end or equivalently shortened end for the RF signal.

18. A method according to claim 12, wherein

said first and second λ

/2 resonator is an electronic circuit providing a delay at the feeding point equivalent to one wavelength λ

.

19. A method according to claim 12, wherein

said first and second λ

/2 resonator is each one arm of a dipole antenna.

20. A method according to claim 12 further comprising the step of

changing the switch rate for selecting a predetermined modulated signal from a plurality of adjacent RF channels according to:

$f_{\mathrm{IF}}=\{\begin{array}{cc}\mathrm{frac}<br><br>\left(\frac{f_{\mathrm{RF}}}{f_p}\right)·<br><br>f_p& \mathrm{frac}<br><br>\left(\frac{f_{\mathrm{RF}}}{f_p}\right)<<br><br>0.5\\ \left(1-\mathrm{frac}<br><br>\left(\frac{f_{\mathrm{RF}}}{f_p}\right)\right)·<br><br>f_p& \mathrm{else}\end{array}$

wherein,

f_IF is intermediate frequency of the down-converted signal,

f_RF centre frequency of the RF channel,

f_p is the switch rate, and

frac(x) is the fractional part of the argument x.

21. A method according to claim 20, further comprising the step of

filtering the intermediate frequency by a bandpass filter.