A 0.1–1.5GHz harmonic rejection receiver front-end with hybrid 8 phase LO generator, phase ambiguity correction and vector gain calibration

Abstract

A 0.1-1.5GHz harmonic rejection (HR) receiver front-end is presented. A flexible HR mixer is proposed to correct phase ambiguity, and a vector gain calibration is used to eliminate the gain/phase mismatch and improve the HR ratio. With the proposed hybrid 8 phase local oscillating (LO) generator, the highest carrier frequency from the frequency synthesizer is only twice of the desired LO frequency. The HR receiver has been implemented in 65nm CMOS. With 1.8mm 2 core chip area and 5.4-24.5mA current consumption from a 1.2V power supply, the receiver achieves 85dB conversion gain, 4.3dB NF, +13dBm/+14dBm IB/OB-IIP3, >54/56 dB HR3/HR5 with 30-40dB improvement by calibration, and 2.3% EVM with 32QAM modulation signal.

A 0.1–5.0 GHz flexible SDR receiver with digitally assisted calibration in 65 nm CMOS

“…For the low frequency band HR path, an improvement of about 30-40dB rejection is achieved with auto calibration. Compare with [27], the auto calibration achieves similar HR improvement with the manual calibration. For the high frequency band HR path, auto calibration is limited by the noise floor of the ADC.…”

“…15, to calibrate the HR3 or HR5, one test tone (f RF =3*f LO +5 MHz or f RF =5*f LO +5 MHz) is applied to the receiver RF port. The gain adjustment of 0° path and 90° path is realized with variable gain TCA 1 and TCA 3 [27] in Fig. 15.…”

“…More measured results are shown to evaluate the complete performances in detail. The HR path is the same with [27]. However, the HR calibration is manual in [27] while the HR calibrations are automatically executed in a digitally assisted closed-loop form.…”