使用AD5934扫频测量电阻，但是在起始频率附近电阻测量不准确，有较大波动。下图是连续扫频的结果，起始频率50kHz,增量2Hz,增量数300。设置其他起始频率也是一样的结果。
但是使用官方的评估板却没有这个问题。请问是什么原因？
1.AD5934的程序是参考这个的：ad5933/User at master · edaworld/ad5933 (github.com)
这是扫频部分的代码
2.这是自己画的原理图和PCB
使用AD5934扫频测量电阻，但是在起始频率附近电阻测量不准确，有较大波动。下图是连续扫频的结果，起始频率50kHz,增量2Hz,增量数300。设置其他起始频率也是一样的结果。
但是使用官方的评估板却没有这个问题。请问是什么原因？
1.AD5934的程序是参考这个的：ad5933/User at master · edaworld/ad5933 (github.com)
这是扫频部分的代码
2.这是自己画的原理图和PCB
From the provided brief description it is quite difficult to diagnose the issue. First thing to try would be adding a delay after calling the AD5933_Set_Mode_Freq_Start() function. It takes some time for the C1R1R2 circuit to transition to the Vdd/2 DC level after the AD5933 comes out of Standby Mode. Adding 6-10 millisecond delay might help.
Thanks for your answer. But i add a delay after calling the AD5933_Set_Mode_Freq_Start、Init_AD5933、AD5933_Set_Mode_Freq_Start_UP function.And try different delay time.The problem still exists.
Could it be the cause of PCB layout?
PCB layout is not the likely cause of it. If adding the delay did not help, we can try to debug a bit more systematically. Can you please post the following information:
1. Is your chip the AD5933 or AD5934?
2. What is the MCLK frequency?
3. What is the Number of Settling Cycles? The code you linked in your post does not seem to write anything into registers 0x8A and 0x8B. This number should not be 0, please see the datasheet, p. 15 under FREQUENCY SWEEP COMMAND SEQUENCE, paragraph 3.
4. Was the graph you posted collected with a resistor connected to J1 or some different impedance?
5. Is RFB1 value 100Ω?
Can you also post a text file with the raw "real" and "img" data which you are collecting and printing? Can you get and post this data when nothing is connected to J1 and then when a resistor of 100Ω is connected to J1? It can be done through uploading via Insert->Image/video/file.
1. my chip is AD5934
2. MCLK is 16MHz
3. the Number of Settling Cycles ，I set it 15.
4. Yes, J1 is pin header. I use it to connecte resistor.
5. RFB1 is 1000Ω, and the resistor connected by J1 also 1000Ω.
6. I print the raw "real" and "img" data. There's nothing wrong with drawing.
①I've been changing the starting frequency around 50k.But yesterday, I realized that the problem wasn't at the starting frequency.
I set the starting frequency to 50K, 49K, 48K, and found that the problem kept happening at 50K
② So I started to see if there were other frequencies that had the same problem.
The same problem occurs around 63K and 83K
When the frequency is below 45K, the result is completely wrong
Sorry, the frequency below 45K is a drawing error, the symbol was not considered when the imaginary data was converted to int
calibration factor：4.88e-7 start:49k add:10 num:200 RFB:1000Ω J1：connect 1000Ω 1 Real: 0x7 0xef Img: 0x0 0xf0 1001.8567823321512 2 Real: 0x7 0xed Img: 0x0 0xef 1002.8882404525632 3 Real: 0x7 0xf5 Img: 0x0 0xe9 999.3395986737224 4 Real: 0x7 0xf0 Img: 0x0 0xed 1001.5417070470622 5 Real: 0x7 0xe9 Img: 0x0 0xef 1004.8420646539487 6 Real: 0x7 0xee Img: 0x0 0xf3 1002.1697575901594 7 Real: 0x7 0xeb Img: 0x0 0xf5 1003.5144961269511 8 Real: 0x7 0xee Img: 0x0 0xf4 1002.1113819940739 9 Real: 0x7 0xe5 Img: 0x0 0xf5 1006.4506711684356 10 Real: 0x7 0xe9 Img: 0x0 0xf3 1004.6091665902647 11 Real: 0x7 0xee Img: 0x0 0xf2 1002.2279035907484 12 Real: 0x7 0xec Img: 0x0 0xf3 1003.1441084040279 13 Real: 0x7 0xed Img: 0x0 0xf6 1002.4806265424493 14 Real: 0x7 0xee Img: 0x0 0xf7 1001.9348788621776 15 Real: 0x7 0xec Img: 0x0 0xf8 1002.8490783307927 16 Real: 0x7 0xea Img: 0x0 0xfa 1003.7044804222376 17 Real: 0x7 0xea Img: 0x0 0xf8 1003.8244500252264 18 Real: 0x7 0xee Img: 0x0 0xf1 1002.2858198735732 19 Real: 0x7 0xe4 Img: 0x0 0xf2 1007.1193955814293 20 Real: 0x7 0xea Img: 0x0 0xf7 1003.8840894773707 21 Real: 0x7 0xea Img: 0x0 0xf9 1003.7645802981383 22 Real: 0x7 0xe8 Img: 0x0 0xf9 1004.7416618629062 23 Real: 0x7 0xf0 Img: 0x0 0xf9 1000.8446192641413 24 Real: 0x7 0xee Img: 0x0 0xfd 1001.5756902255804 25 Real: 0x7 0xee Img: 0x0 0xf8 1001.8755861156612 26 Real: 0x7 0xef Img: 0x0 0xff 1000.9687023878292 27 Real: 0x7 0xec Img: 0x0 0xff 1002.4263955448483 28 Real: 0x7 0xe9 Img: 0x0 0xff 1003.8883068107194 29 Real: 0x7 0xed Img: 0x0 0xfe 1002.0010116751675 30 Real: 0x7 0xee Img: 0x1 0x0 1001.3930115023387 31 Real: 0x7 0xf0 Img: 0x1 0x6 1000.0523646931587 32 Real: 0x7 0xe8 Img: 0x1 0x1 1004.2530058432823 33 Real: 0x7 0xe8 Img: 0x1 0x3 1004.1285415406825 34 Real: 0x7 0xea Img: 0x1 0x9 1002.7754515486937 35 Real: 0x7 0xea Img: 0x1 0x2 1003.2154113398078 36 Real: 0x7 0xe9 Img: 0x1 0x9 1003.2623136336651 37 Real: 0x7 0xe9 Img: 0x1 0x7 1003.3893436422875 38 Real: 0x7 0xec Img: 0x1 0x9 1001.803131496524 39 Real: 0x7 0xef Img: 0x1 0x4 1000.6612661581044 40 Real: 0x7 0xe4 Img: 0x1 0x7 1005.8316312463403 41 Real: 0x7 0xee Img: 0x1 0x9 1000.8326791455657 42 Real: 0x7 0xe7 Img: 0x1 0xc 1004.0446266241889 43 Real: 0x7 0xea Img: 0x1 0x9 1002.7754515486937 44 Real: 0x7 0xee Img: 0x1 0x7 1000.958788372842 45 Real: 0x7 0xea Img: 0x1 0xa 1002.7116868059289 46 Real: 0x7 0xf1 Img: 0x1 0xb 999.2540265250834 47 Real: 0x7 0xe6 Img: 0x1 0xd 1004.4677914471159 48 Real: 0x7 0xec Img: 0x1 0x9 1001.803131496524 49 Real: 0x7 0xeb Img: 0x1 0xd 1002.0330045286013 50 Real: 0x7 0xe9 Img: 0x1 0xf 1002.8757465165916 51 Real: 0x7 0xe9 Img: 0x1 0xf 1002.8757465165916 52 Real: 0x7 0xe7 Img: 0x1 0x11 1003.7186914423673 53 Real: 0x7 0xe7 Img: 0x1 0x13 1003.586720789359 54 Real: 0x7 0xe7 Img: 0x1 0x14 1003.5203938896632 55 Real: 0x7 0xea Img: 0x1 0x14 1002.0615250862734 56 Real: 0x7 0xe1 Img: 0x1 0x17 1006.2486873927089 57 Real: 0x7 0xeb Img: 0x1 0x13 1001.6421110012716 58 Real: 0x7 0xe8 Img: 0x1 0x15 1002.9671792844433 59 Real: 0x7 0xe6 Img: 0x1 0x11 1004.2062056956862 60 Real: 0x7 0xe7 Img: 0x1 0x17 1003.3200485654021 61 Real: 0x7 0xe7 Img: 0x1 0x19 1003.185349226433 62 Real: 0x7 0xe4 Img: 0x1 0x17 1004.7822543128117 63 Real: 0x7 0xe3 Img: 0x1 0x17 1005.2705947402962 64 Real: 0x7 0xe4 Img: 0x1 0x14 1004.9834770201816 65 Real: 0x7 0xe5 Img: 0x1 0x1c 1003.9549477326518 66 Real: 0x7 0xe6 Img: 0x1 0x16 1003.874088585043 67 Real: 0x7 0xe4 Img: 0x1 0x1d 1004.3736549508861 68 Real: 0x7 0xe6 Img: 0x1 0x19 1003.6720863699717 69 Real: 0x7 0xe5 Img: 0x1 0x1a 1004.0914041836155 70 Real: 0x7 0xe6 Img: 0x1 0x18 1003.7396477767794 71 Real: 0x7 0xea Img: 0x1 0x1b 1001.5929224547109 72 Real: 0x7 0xe8 Img: 0x1 0x1b 1002.563669815222 73 Real: 0x7 0xe3 Img: 0x1 0x27 1004.1612209999915 74 Real: 0x7 0xe6 Img: 0x1 0x18 1003.7396477767794 75 Real: 0x7 0xeb Img: 0x1 0x1f 1000.8359029354668 76 Real: 0x7 0xe9 Img: 0x1 0x1e 1001.8735499860762 77 Real: 0x7 0xe6 Img: 0x1 0x1a 1003.6042978163365 78 Real: 0x7 0xe6 Img: 0x1 0x20 1003.1928043785464 79 Real: 0x7 0xe8 Img: 0x1 0x1f 1002.290137017231 80 Real: 0x7 0xe7 Img: 0x1 0x19 1003.185349226433 81 Real: 0x7 0xe5 Img: 0x1 0x25 1003.3296720231166 82 Real: 0x7 0xe6 Img: 0x1 0x29 1002.5603092821638 83 Real: 0x7 0xe5 Img: 0x1 0x27 1003.1882350720507 84 Real: 0x7 0xe3 Img: 0x1 0x21 1004.5840503347118 85 Real: 0x7 0xe5 Img: 0x1 0x29 1003.045896373531 86 Real: 0x7 0xe6 Img: 0x1 0x2a 1002.4889059425756 87 Real: 0x7 0xe5 Img: 0x1 0x2c 1002.8307001437587 88 Real: 0x7 0xe2 Img: 0x1 0x2b 1004.3615880833207 89 Real: 0x7 0xe2 Img: 0x1 0x2a 1004.4336337357497 90 Real: 0x7 0xe9 Img: 0x1 0x2c 1000.8923840122355 91 Real: 0x7 0xe3 Img: 0x1 0x2a 1003.9467524732704 92 Real: 0x7 0xe2 Img: 0x1 0x30 1003.9979761372962 93 Real: 0x7 0xd9 Img: 0x1 0x45 1006.7859606879972 94 Real: 0x7 0xce Img: 0x1 0x22 1014.8553750385149 95 Real: 0x7 0xd3 Img: 0x1 0x7 1014.2243099780495 96 Real: 0x7 0xee Img: 0x0 0xd3 1003.9159015319608 97 Real: 0x8 0x2a Img: 0x0 0xac 977.0454681015641 98 Real: 0x8 0x39 Img: 0x1 0x18 964.8642166822132 99 Real: 0x8 0x4c Img: 0x0 0xfb 957.9896283035772 100 Real: 0x7 0xb7 Img: 0x1 0xed 1006.5468504101384 101 Real: 0x7 0x96 Img: 0x1 0xf1 1022.1194694476433 102 Real: 0x7 0x28 Img: 0x2 0x6 1076.217021639801 103 Real: 0x7 0xb2 Img: 0x0 0xc6 1034.8513961245383 104 Real: 0x7 0x92 Img: 0x1 0x26 1045.2791298109375 105 Real: 0x8 0x1e Img: 0x0 0xa7 982.8410165902657 106 Real: 0x8 0x18 Img: 0x0 0xcd 984.0604205381178 107 Real: 0x8 0x17 Img: 0x0 0xff 981.927177443488 108 Real: 0x7 0xfb Img: 0x1 0x36 991.551875797629 109 Real: 0x7 0xee Img: 0x1 0x2e 998.3371711902747 110 Real: 0x7 0xe5 Img: 0x1 0x3e 1001.4971991020578 111 Real: 0x7 0xe4 Img: 0x1 0x37 1002.5089453398076 112 Real: 0x7 0xe7 Img: 0x1 0x39 1000.9075507501367 113 Real: 0x7 0xe6 Img: 0x1 0x3c 1001.1653713117258 114 Real: 0x7 0xe7 Img: 0x1 0x38 1000.9822002552753 115 Real: 0x7 0xdf Img: 0x1 0x3b 1004.6362169723709 116 Real: 0x7 0xe2 Img: 0x1 0x3b 1003.1782549618226 117 Real: 0x7 0xe1 Img: 0x1 0x3c 1003.5878042780105 118 Real: 0x7 0xe3 Img: 0x1 0x3c 1002.617442940421 119 Real: 0x7 0xe1 Img: 0x1 0x3d 1003.5116074647856 120 Real: 0x7 0xe1 Img: 0x1 0x3f 1003.358544057826 121 Real: 0x7 0xe2 Img: 0x1 0x40 1002.7967091663993 122 Real: 0x7 0xdd Img: 0x1 0x3d 1005.4574622297341 123 Real: 0x7 0xe0 Img: 0x1 0x41 1003.6899087317968 124 Real: 0x7 0xe0 Img: 0x1 0x41 1003.6899087317968 125 Real: 0x7 0xdf Img: 0x1 0x43 1004.0203964899297 126 Real: 0x7 0xe1 Img: 0x1 0x43 1003.0497425687907 127 Real: 0x7 0xdc Img: 0x1 0x43 1005.4798594324113 128 Real: 0x7 0xde Img: 0x1 0x45 1004.3500042996264 129 Real: 0x7 0xdf Img: 0x1 0x44 1003.9424138877877 130 Real: 0x7 0xe1 Img: 0x1 0x45 1002.8940070420451 131 Real: 0x7 0xe0 Img: 0x1 0x44 1003.4569683042407 132 Real: 0x7 0xde Img: 0x1 0x46 1004.2714623395635 133 Real: 0x7 0xde Img: 0x1 0x47 1004.1926975916188 134 Real: 0x7 0xe0 Img: 0x1 0x47 1003.2220253674445 135 Real: 0x7 0xe0 Img: 0x1 0x49 1003.0642863945801 136 Real: 0x7 0xe1 Img: 0x1 0x50 1002.0216209523965 137 Real: 0x7 0xe9 Img: 0x1 0x4f 998.2487758637632 138 Real: 0x7 0xdf Img: 0x1 0x4b 1003.3903061750048 139 Real: 0x7 0xe4 Img: 0x1 0x4b 1000.9716885946497 140 Real: 0x7 0xe0 Img: 0x1 0x53 1002.2623164033862 141 Real: 0x7 0xe0 Img: 0x1 0x4d 1002.746149478338 142 Real: 0x7 0xdd Img: 0x1 0x4e 1004.1203420294748 143 Real: 0x7 0xde Img: 0x1 0x4f 1003.5545788889307 144 Real: 0x7 0xdc Img: 0x1 0x4c 1004.7669107548804 145 Real: 0x7 0xd7 Img: 0x1 0x59 1006.1341544927103 146 Real: 0x7 0xde Img: 0x1 0x4f 1003.5545788889307 147 Real: 0x7 0xdc Img: 0x1 0x52 1004.2815957506284 148 Real: 0x7 0xde Img: 0x1 0x4c 1003.795537753118 149 Real: 0x7 0xdd Img: 0x1 0x52 1003.7963809923518 150 Real: 0x7 0xdb Img: 0x1 0x53 1004.6854929263594 151 Real: 0x7 0xde Img: 0x1 0x53 1003.2302028915569 152 Real: 0x7 0xe2 Img: 0x1 0x53 1001.2962693627753 153 Real: 0x7 0xde Img: 0x1 0x53 1003.2302028915569 154 Real: 0x7 0xdb Img: 0x1 0x52 1004.767273193025 155 Real: 0x7 0xdb Img: 0x1 0x56 1004.4388235521878 156 Real: 0x7 0xd6 Img: 0x1 0x52 1007.2026235413255 157 Real: 0x7 0xda Img: 0x1 0x59 1004.6754680639253 158 Real: 0x7 0xdd Img: 0x1 0x56 1003.4688822501523 159 Real: 0x7 0xde Img: 0x1 0x59 1002.7370231285998 160 Real: 0x7 0xd7 Img: 0x1 0x56 1006.3842604381151 161 Real: 0x7 0xde Img: 0x1 0x5a 1002.6540568269884 162 Real: 0x7 0xd9 Img: 0x1 0x59 1005.161233625139 163 Real: 0x7 0xd8 Img: 0x1 0x5c 1005.395726339343 164 Real: 0x7 0xdc Img: 0x1 0x5e 1003.2870903209863 165 Real: 0x7 0xd6 Img: 0x1 0x5e 1006.1994237461583 166 Real: 0x7 0xda Img: 0x1 0x56 1004.924487510924 167 Real: 0x7 0xd8 Img: 0x1 0x5b 1005.4798594324113 168 Real: 0x7 0xe1 Img: 0x1 0x59 1001.2880194766664 169 Real: 0x7 0xd8 Img: 0x1 0x60 1005.0569866824164 170 Real: 0x7 0xdb Img: 0x1 0x61 1003.5173848140623 171 Real: 0x7 0xdc Img: 0x1 0x63 1002.8633731748417 172 Real: 0x7 0xde Img: 0x1 0x60 1002.1516564681723 173 Real: 0x7 0xd7 Img: 0x1 0x63 1005.286082385066 174 Real: 0x7 0xdc Img: 0x1 0x62 1002.9485542878899 175 Real: 0x7 0xd2 Img: 0x1 0x65 1007.5468271107997 176 Real: 0x7 0xda Img: 0x1 0x69 1003.3139137556416 177 Real: 0x7 0xdb Img: 0x1 0x62 1003.4322993612767 178 Real: 0x7 0xdc Img: 0x1 0x65 1002.6923556429371 179 Real: 0x7 0xd9 Img: 0x1 0x6b 1003.6233205710257 180 Real: 0x7 0xd6 Img: 0x1 0x6c 1004.9887962569833 181 Real: 0x7 0xd7 Img: 0x1 0x6c 1004.5040048404944 182 Real: 0x7 0xd8 Img: 0x1 0x67 1004.4557211863149 183 Real: 0x7 0xd9 Img: 0x1 0x62 1004.4011690353096 184 Real: 0x7 0xdc Img: 0x1 0x6a 1002.2609973800813 185 Real: 0x7 0xd3 Img: 0x1 0x6c 1006.4459357816387 186 Real: 0x7 0xd7 Img: 0x1 0x67 1004.9406844153867 187 Real: 0x7 0xd2 Img: 0x1 0x6f 1006.6660197537393 188 Real: 0x7 0xd6 Img: 0x1 0x6c 1004.9887962569833 189 Real: 0x7 0xd5 Img: 0x1 0x6d 1005.3858012377374 190 Real: 0x7 0xd7 Img: 0x1 0x6b 1004.5917782127017 191 Real: 0x7 0xda Img: 0x1 0x62 1003.9165040621764 192 Real: 0x7 0xd5 Img: 0x1 0x6d 1005.3858012377374 193 Real: 0x7 0xd8 Img: 0x1 0x6d 1003.9318086934004 194 Real: 0x7 0xd2 Img: 0x1 0x6c 1006.9325728686302 195 Real: 0x7 0xd6 Img: 0x1 0x6d 1004.9006770658514 196 Real: 0x7 0xd2 Img: 0x1 0x6d 1006.843941431783 197 Real: 0x7 0xd8 Img: 0x1 0x73 1003.4000519747788 198 Real: 0x7 0xd7 Img: 0x1 0x72 1003.9727851674318 199 Real: 0x7 0xda Img: 0x1 0x73 1002.4345536280708 200 Real: 0x7 0xd5 Img: 0x1 0x6f 1005.2086513186207 start:49k add:10 num:200 RFB:1000Ω J1：connect 1200Ω 1 Real: 0x7 0x38 Img: 0x0 0x6d 1106.8039047354348 2 Real: 0x7 0x35 Img: 0x0 0x6c 1108.6325456433635 3 Real: 0x7 0x3b Img: 0x0 0x67 1105.2207314921752 4 Real: 0x7 0x35 Img: 0x0 0x6c 1108.6325456433635 5 Real: 0x7 0x3b Img: 0x0 0x6e 1104.9810691126681 6 Real: 0x7 0x36 Img: 0x0 0x6e 1107.9634003276783 7 Real: 0x7 0x34 Img: 0x0 0x6c 1109.2317016539073 8 Real: 0x7 0x35 Img: 0x0 0x6f 1108.5259395495673 9 Real: 0x7 0x34 Img: 0x0 0x73 1108.9780503080399 10 Real: 0x7 0x35 Img: 0x0 0x6c 1108.6325456433635 11 Real: 0x7 0x36 Img: 0x0 0x70 1107.8914830295962 12 Real: 0x7 0x34 Img: 0x0 0x71 1109.0521290576712 13 Real: 0x7 0x34 Img: 0x0 0x70 1109.088686542314 14 Real: 0x7 0x35 Img: 0x0 0x79 1108.1497377433986 15 Real: 0x7 0x36 Img: 0x0 0x73 1107.7812046512845 16 Real: 0x7 0x35 Img: 0x0 0x72 1108.4164447636892 17 Real: 0x7 0x37 Img: 0x0 0x73 1107.183748180096 18 Real: 0x7 0x34 Img: 0x0 0x7a 1108.7086653098024 19 Real: 0x7 0x32 Img: 0x0 0x6c 1110.4319553029832 20 Real: 0x7 0x37 Img: 0x0 0x72 1107.220767872515 21 Real: 0x7 0x34 Img: 0x0 0x71 1109.0521290576712 22 Real: 0x7 0x34 Img: 0x0 0x76 1108.8645241945435 23 Real: 0x7 0x38 Img: 0x0 0x74 1106.5496556638118 24 Real: 0x7 0x37 Img: 0x0 0x77 1107.0324748461694 25 Real: 0x7 0x37 Img: 0x0 0x76 1107.070772167681 26 Real: 0x7 0x32 Img: 0x0 0x78 1109.9860458028177 27 Real: 0x7 0x37 Img: 0x0 0x78 1106.9938583651829 28 Real: 0x7 0x32 Img: 0x0 0x7f 1109.7045326155703 29 Real: 0x7 0x37 Img: 0x0 0x7b 1106.876094976926 30 Real: 0x7 0x33 Img: 0x0 0x78 1109.3863177021387 31 Real: 0x7 0x33 Img: 0x0 0x81 1109.0220733893789 32 Real: 0x7 0x35 Img: 0x0 0x82 1107.7837952486448 33 Real: 0x7 0x33 Img: 0x0 0x83 1108.9376056772664 34 Real: 0x7 0x35 Img: 0x0 0x78 1108.1887995013608 35 Real: 0x7 0x34 Img: 0x0 0x7f 1108.5066336682676 36 Real: 0x7 0x35 Img: 0x0 0x85 1107.656068061965 37 Real: 0x7 0x35 Img: 0x0 0x7d 1107.9902919236704 38 Real: 0x7 0x36 Img: 0x0 0x80 1107.2700793433175 39 Real: 0x7 0x33 Img: 0x0 0x82 1108.9799995586447 40 Real: 0x7 0x35 Img: 0x0 0x81 1107.8257330718798 41 Real: 0x7 0x3b Img: 0x0 0x82 1104.2105777800605 42 Real: 0x7 0x37 Img: 0x0 0x85 1106.4628475488184 43 Real: 0x7 0x35 Img: 0x0 0x84 1107.6989626330371 44 Real: 0x7 0x3a Img: 0x0 0x81 1104.8461166955556 45 Real: 0x7 0x35 Img: 0x0 0x86 1107.6128547975957 46 Real: 0x7 0x38 Img: 0x0 0x82 1105.9943075984681 47 Real: 0x7 0x36 Img: 0x0 0x83 1107.1444693354458 48 Real: 0x7 0x37 Img: 0x0 0x80 1106.6734490366532 49 Real: 0x7 0x34 Img: 0x0 0x87 1108.1667558438528 50 Real: 0x7 0x33 Img: 0x0 0x88 1108.7208394185689 51 Real: 0x7 0x33 Img: 0x0 0x88 1108.7208394185689 52 Real: 0x7 0x32 Img: 0x0 0x89 1109.2751046796034 53 Real: 0x7 0x34 Img: 0x0 0x8c 1107.9439618390118 54 Real: 0x7 0x33 Img: 0x0 0x8b 1108.5869462744945 55 Real: 0x7 0x38 Img: 0x0 0x88 1105.7372345435151 56 Real: 0x7 0x32 Img: 0x0 0x8c 1109.1400356030151 57 Real: 0x7 0x35 Img: 0x0 0x8f 1107.209613076505 58 Real: 0x7 0x33 Img: 0x0 0x8e 1108.450181920491 59 Real: 0x7 0x2d Img: 0x0 0x8c 1112.1415158095167 60 Real: 0x7 0x31 Img: 0x0 0x8e 1109.647246740885 61 Real: 0x7 0x32 Img: 0x0 0x8d 1109.0943735870676 62 Real: 0x7 0x33 Img: 0x0 0x8b 1108.5869462744945 63 Real: 0x7 0x2f Img: 0x0 0x8f 1110.8003660707961 64 Real: 0x7 0x33 Img: 0x0 0x8d 1108.49608886493 65 Real: 0x7 0x31 Img: 0x0 0x90 1109.5541761133165 66 Real: 0x7 0x33 Img: 0x0 0x8f 1108.4039563090048 67 Real: 0x7 0x34 Img: 0x0 0x93 1107.618681010159 68 Real: 0x7 0x33 Img: 0x0 0x91 1108.3105495678888 69 Real: 0x7 0x34 Img: 0x0 0x90 1107.7599948189484 70 Real: 0x7 0x30 Img: 0x0 0x91 1110.106434047306 71 Real: 0x7 0x35 Img: 0x0 0x95 1106.9264911679518 72 Real: 0x7 0x2f Img: 0x0 0x92 1110.658864720453 73 Real: 0x7 0x33 Img: 0x0 0x8a 1108.631896502548 74 Real: 0x7 0x36 Img: 0x0 0x98 1106.1851343250887 75 Real: 0x7 0x32 Img: 0x0 0x9c 1108.3711963950432 76 Real: 0x7 0x38 Img: 0x0 0x92 1105.2834455749066 77 Real: 0x7 0x39 Img: 0x0 0x9b 1104.2546769946814 78 Real: 0x7 0x35 Img: 0x0 0x98 1106.7806518265859 79 Real: 0x7 0x35 Img: 0x0 0x95 1106.9264911679518 80 Real: 0x7 0x33 Img: 0x0 0x91 1108.3105495678888 81 Real: 0x7 0x34 Img: 0x0 0x9c 1107.1776055335683 82 Real: 0x7 0x2f Img: 0x0 0x9b 1110.217082411289 83 Real: 0x7 0x33 Img: 0x0 0x9b 1107.8244376238122 84 Real: 0x7 0x2f Img: 0x0 0x9c 1110.1663984208926 85 Real: 0x7 0x2e Img: 0x0 0x9c 1110.7660874239787 86 Real: 0x7 0x31 Img: 0x0 0x9b 1109.0194740950337 87 Real: 0x7 0x30 Img: 0x0 0xa1 1109.3095706361144 88 Real: 0x7 0x2f Img: 0x0 0xa2 1109.8556015507593 89 Real: 0x7 0x32 Img: 0x0 0x9a 1108.4717558518419 90 Real: 0x7 0x2d Img: 0x0 0x9e 1111.263765520564 91 Real: 0x7 0x2b Img: 0x0 0x9e 1112.4660435651303 92 Real: 0x7 0x2d Img: 0x0 0xa9 1110.6763250532053 93 Real: 0x7 0x2a Img: 0x0 0x9b 1113.222409457735 94 Real: 0x7 0x25 Img: 0x0 0x8b 1117.0240315493668 95 Real: 0x7 0x26 Img: 0x0 0x6c 1117.6882853218426 96 Real: 0x7 0x3c Img: 0x0 0x3f 1105.6932794722295 97 Real: 0x7 0x6c Img: 0x0 0x53 1077.355899159025 98 Real: 0x7 0x6d Img: 0x0 0xe2 1070.2791933280428 99 Real: 0x7 0x7a Img: 0x0 0xd9 1063.6811041976234 100 Real: 0x7 0x79 Img: 0x0 0xef 1062.7928274943108 101 Real: 0x6 0xc9 Img: 0x1 0x20 1163.691929138497 102 Real: 0x6 0xd6 Img: 0x0 0x87 1167.3479311223991 103 Real: 0x6 0xd2 Img: 0x1 0x1a 1158.4855880690225 104 Real: 0x7 0x5 Img: 0x0 0x37 1139.6602142437528 105 Real: 0x7 0xb Img: 0x0 0x5c 1134.9230458535876 106 Real: 0x7 0x5d Img: 0x0 0x5e 1085.6156819417442 107 Real: 0x7 0x56 Img: 0x0 0x8f 1087.8670051458537 108 Real: 0x7 0x3f Img: 0x0 0xbc 1098.9143640437342 109 Real: 0x7 0x34 Img: 0x0 0xc3 1104.9714280142819 110 Real: 0x7 0x34 Img: 0x0 0xb6 1105.7597776392302 111 Real: 0x7 0x35 Img: 0x0 0xab 1105.7910182082042 112 Real: 0x7 0x32 Img: 0x0 0xaa 1107.63179032459 113 Real: 0x7 0x34 Img: 0x0 0xb0 1106.1058260901361 114 Real: 0x7 0x32 Img: 0x0 0xb2 1107.1814850879016 115 Real: 0x7 0x31 Img: 0x0 0xb0 1107.8919689102945 116 Real: 0x7 0x2f Img: 0x0 0xae 1109.1996809647007 117 Real: 0x7 0x31 Img: 0x0 0xb2 1107.7773187893215 118 Real: 0x7 0x33 Img: 0x0 0xb1 1106.6435863376514 119 Real: 0x7 0x2f Img: 0x0 0xb3 1108.9129187603821 120 Real: 0x7 0x30 Img: 0x0 0xb3 1108.315900358075 121 Real: 0x7 0x30 Img: 0x0 0xb5 1108.1991734424394 122 Real: 0x7 0x2c Img: 0x0 0xb3 1110.7078210067607 123 Real: 0x7 0x2d Img: 0x0 0xb7 1109.873024026736 124 Real: 0x7 0x30 Img: 0x0 0xb4 1108.2576944106718 125 Real: 0x7 0x31 Img: 0x0 0xb4 1107.661409378428 126 Real: 0x7 0x32 Img: 0x0 0xb9 1106.7709635471015 127 Real: 0x7 0x2b Img: 0x0 0xb5 1111.1897329723881 128 Real: 0x7 0x2e Img: 0x0 0xb8 1109.2154471503918 129 Real: 0x7 0x2f Img: 0x0 0xb5 1108.7960031305652 130 Real: 0x7 0x30 Img: 0x0 0xba 1107.9018486231487 131 Real: 0x7 0x31 Img: 0x0 0xba 1107.306137473803 132 Real: 0x7 0x36 Img: 0x0 0xb9 1104.3966321557325 133 Real: 0x7 0x2e Img: 0x0 0xbc 1108.973664531759 134 Real: 0x7 0x2e Img: 0x0 0xbb 1109.0345827490407 135 Real: 0x7 0x2f Img: 0x0 0xbe 1108.2542898898498 136 Real: 0x7 0x36 Img: 0x0 0xc2 1103.8498041744192 137 Real: 0x7 0x3a Img: 0x0 0xbc 1101.8540854128232 138 Real: 0x7 0x2f Img: 0x0 0xc0 1108.130451510669 139 Real: 0x7 0x2d Img: 0x0 0xbb 1109.632113033963 140 Real: 0x7 0x32 Img: 0x0 0xba 1106.7110633353993 141 Real: 0x7 0x2c Img: 0x0 0xbd 1110.1077375173259 142 Real: 0x7 0x31 Img: 0x0 0xbe 1107.0630154271573 143 Real: 0x7 0x2b Img: 0x0 0xbe 1110.6445054377073 144 Real: 0x7 0x30 Img: 0x0 0xc5 1107.220121208468 145 Real: 0x7 0x36 Img: 0x0 0xb9 1104.3966321557325 146 Real: 0x7 0x2e Img: 0x0 0xc0 1108.726845459951 147 Real: 0x7 0x30 Img: 0x0 0xc0 1107.5346953363107 148 Real: 0x7 0x2b Img: 0x0 0xc3 1110.3305354044162 149 Real: 0x7 0x2d Img: 0x0 0xc2 1109.1983806907358 150 Real: 0x7 0x2e Img: 0x0 0xc7 1108.2828239872183 151 Real: 0x7 0x2f Img: 0x0 0xc5 1107.8153696145848 152 Real: 0x7 0x27 Img: 0x0 0xc9 1112.3393128154412 153 Real: 0x7 0x2e Img: 0x0 0xc5 1108.4112547052864 154 Real: 0x7 0x2d Img: 0x0 0xc6 1108.943615242084 155 Real: 0x7 0x2c Img: 0x0 0xc8 1109.4111988775267 156 Real: 0x7 0x2b Img: 0x0 0xce 1109.612098437086 157 Real: 0x7 0x2b Img: 0x0 0xc9 1109.9433735826044 158 Real: 0x7 0x2a Img: 0x0 0xc7 1110.671919097169 159 Real: 0x7 0x30 Img: 0x0 0xcb 1106.8323269477758 160 Real: 0x7 0x28 Img: 0x0 0xc9 1111.739364630975 161 Real: 0x7 0x2b Img: 0x0 0xd1 1109.4095726057794 162 Real: 0x7 0x29 Img: 0x0 0xcc 1110.941594914941 163 Real: 0x7 0x2c Img: 0x0 0xcd 1109.0820246868661 164 Real: 0x7 0x28 Img: 0x0 0xcb 1111.607156163292 165 Real: 0x7 0x2b Img: 0x0 0xcf 1109.5449028757969 166 Real: 0x7 0x2f Img: 0x0 0xce 1107.2285279294563 167 Real: 0x7 0x27 Img: 0x0 0xcf 1111.938257034488 168 Real: 0x7 0x25 Img: 0x0 0xcb 1113.408289869144 169 Real: 0x7 0x29 Img: 0x0 0xd0 1110.672571828088 170 Real: 0x7 0x2b Img: 0x0 0xd0 1109.4773942072243 171 Real: 0x7 0x27 Img: 0x0 0xd1 1111.8020492354387 172 Real: 0x7 0x30 Img: 0x0 0xd0 1106.5006017276294 173 Real: 0x7 0x2c Img: 0x0 0xd0 1108.8807632753812 174 Real: 0x7 0x2d Img: 0x0 0xcf 1108.3520607595751 175 Real: 0x7 0x25 Img: 0x0 0xdc 1112.2280287732897 176 Real: 0x7 0x2c Img: 0x0 0xd8 1108.3303316634272 177 Real: 0x7 0x2b Img: 0x0 0xd5 1109.1351603857765 178 Real: 0x7 0x2a Img: 0x0 0xd7 1109.5925730447896 179 Real: 0x7 0x2c Img: 0x0 0xd6 1108.469809280019 180 Real: 0x7 0x27 Img: 0x0 0xd2 1111.7334731506105 181 Real: 0x7 0x27 Img: 0x0 0xd6 1111.456025066772 182 Real: 0x7 0x2b Img: 0x0 0xd8 1108.9260740832576 183 Real: 0x7 0x29 Img: 0x0 0xe2 1109.3999777480442 184 Real: 0x7 0x2a Img: 0x0 0xd6 1109.6623810670267 185 Real: 0x7 0x29 Img: 0x0 0xdb 1109.906894365296 186 Real: 0x7 0x29 Img: 0x0 0xda 1109.978064746254 187 Real: 0x7 0x29 Img: 0x0 0xdd 1109.7636179672427 188 Real: 0x7 0x27 Img: 0x0 0xd8 1111.3154172964132 189 Real: 0x7 0x28 Img: 0x0 0xdb 1110.5042053941647 190 Real: 0x7 0x29 Img: 0x0 0xd9 1110.0489230034777 191 Real: 0x7 0x27 Img: 0x0 0xda 1111.17355564383 192 Real: 0x7 0x2a Img: 0x0 0xdb 1109.3102209680608 193 Real: 0x7 0x29 Img: 0x0 0xe0 1109.5463670557372 194 Real: 0x7 0x26 Img: 0x0 0xde 1111.484316566753 195 Real: 0x7 0x2d Img: 0x0 0xdd 1107.3816607579097 196 Real: 0x7 0x2c Img: 0x0 0xdc 1108.0476456029046 197 Real: 0x7 0x26 Img: 0x0 0xdd 1111.5567722812698 198 Real: 0x7 0x2a Img: 0x0 0xe1 1108.8773530092242 199 Real: 0x7 0x2e Img: 0x0 0xe0 1106.5722484864973 200 Real: 0x7 0x2b Img: 0x0 0xdd 1108.5713691318772
start:49k add:10 num:200
RFB:1000Ω
J1 connect 1000Ω and 1200Ω
Thanks for providing all this info and measurement results - all appears ok, except for the spikes. It begins to look like a real interference smothering your signal around 50 KHz. Do you have access to an oscilloscope to check whether the voltage at the AD5933 RFB pin (pin 4) is a well-formed, clean sine wave without any spikes and noise? Could the interference be coming from some pulse power supply? Your OPAMPs are supposed to be stable at unity gain, but it is still worth checking the voltage at both OPAMP's outputs to see if there may be some self-oscillation.
One more thing to check: are you using the Fre_To_Hex() function from the repository ad5933/User at master · edaworld/ad5933 (github.com) to calculate the Frequency Codes? For the AD5934 it should be
dat = (2147483648 / (double)(AD5933_MCLK * 1000000)) * fre;
Again, worth checking with the oscilloscope if the chip outputs the excitation frequency you programing in.
