ADS1298R: Internal Respiration issue

Dears

we try to test ADS1298R Respiration function with Internal Respiration Circuitry with Internal Clock

fortunately  we make it but we see little pulse appear in each channel when enable Respiration function,

after we turn off Respiration ,  these channel back normal as you can see right snap.

looking forward your reply and golden advice. appendix my register setting for your reference.

ECG-MODE：

#define  config1                           0x04       

#define  config2                           0x10            

#define  config3                           0xFC

#define  loff                              0xef

#define  ch1set                            0x00            

#define  ch2set                            0x00            

#define  ch3set                            0x00            

#define  ch4set                            0x00            

#define  ch5set                            0x00            

#define  ch6set                            0x00             

#define  ch7set                            0x00            

#define  ch8set                            0x00            

#define  rld_sensp                         0x06

#define  rld_sensn                         0x02

#define  loff_sensp_ecg                    0xff

#define  loff_sensn_ecg                    0xff

#define  loff_flip                         0x00            

#define  gpio                             0x08            

#define  pace                             0x03            

#define  resp_ecg                         0x00           

#define  config4_ecg                      0x22           

#define  wct1                             0x0B           

#define  wct2                             0xD4        

Respiration -MODE：

#define  config1                           0x04       

#define  config2                           0x10            

#define  config3                           0xFC

#define  loff                              0xef

#define  ch1set                        0x60

#define  ch2set                            0x00            

#define  ch3set                            0x00            

#define  ch4set                            0x00            

#define  ch5set                            0x00            

#define  ch6set                            0x00            

#define  ch7set                            0x00            

#define  ch8set                            0x00            

#define  rld_sensp                         0x06

#define  rld_sensn                         0x02