Calculate Ratiometric Outputs
abstract: the ds1802 is a dual audio taper-potentiometer with logarithmic resistive characteristics over the device range. each potentiometer provides 65 wiper positions with a 1db increment per step and device mute with at least 90db of attenuation. the specifications given in this datasheet only refer to decibel measurements. if a designer wishes to calculate these values in ratiometric terms, a conversion is necessary. this application note reviews the conversion from decibel to ratiometric. the formula is given in excel as an example, for engineers wishing to build excel tables depicting gain calculations for the ds1802 and other audio potentiometers. while the ds1802 is given as an example, this application note pertains to any audio taper potentiometer.
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overviewthe ds1802 is a dual audio taper-potentiometer with logarithmic resistive characteristics over the device range. each potentiometer provides 65 wiper positions with a 1db increment per step and device mute with at least 90db of attenuation. table 1 shows the db output as a function of the potentiometer wiper setting.
table 1. ds1802 gain (db) as a function of wiper setting - resistance characteristics position output level (db)
0 0
1 -1
2 -2
3 -3
4 -4
5 -5
• •
• •
• •
63 -63
64 (mute) < -90
this chart only gives the output as a function of db attenuation with reference to 0db attenuation at the wiper 0 position. if the ratiometric output is desired, the ratio of the output signal relative to the input signal, a conversion must be made to convert db to a ratiometric attenuation value.
db attenuation is defined as 20 x log(vout/vin).
the desired ratiometric output is defined as:
rl/ree = rl/(rl + rh) = vout/vin
with rh = defined as the high-side of the ds1802, rl defined as the low side of the ds1802, ree defined as the end-to-end resistance, and vout and vin defined as the output and input signals, respectively, as shown in figure 1.
figure 1. ds1802 block diagram (one potentiometer shown).
if we know the db attenuation for a given potentiometer setting, we can calculate the ratiometric output by solving for vout/vin or:
the ratiometric output = inverse log10(db attenuation/20). if one wanted to calculate the output signal ratiometrically as a function of the input in a spreadsheet like excel, no function for the inverse log function exists. as the inverse log function of x can be calculated as 10x, in excel the power function can be used as follows: = (10)^(db/20), where db can be a value stored in another cell in the spreadsheet.
table 2 below summarizes the ratiometric outputs available for the ds1802. while this example is given for the ds1802, it may be used in calculations to determine the ratiometric output of any log potentiometer.
table 2. ratiometric output of the ds1802 as a function of db (wiper) setting db attenuation ratiometric output db attenuation ratiometric output
0 1.00000 -32 0.02512
-1 0.89125 -33 0.02239
-2 0.79433 -34 0.01995
-3 0.70795 -35 0.01778
-4 0.63096 -36 0.01585
-5 0.56234 -37 0.01413
-6 0.50119 -38 0.01259
-7 0.44668 -39 0.01122
-8 0.39811 -40 0.01000
-9 0.35481 -41 0.00891
-10 0.31623 -42 0.00794
-11 0.28184 -43 0.00708
-12 0.25119 -44 0.00631
-13 0.22387 -45 0.00562
-14 0.19953 -46 0.00501
-15 0.17783 -47 0.00447
-16 0.15849 -48 0.00398
-17 0.14125 -49 0.00355
-18 0.12589 -50 0.00316
-19 0.11220 -51 0.00282
-20 0.10000 -52 0.00251
-21 0.08913 -53 0.00224
-22 0.07943 -54 0.00200
-23 0.07079 -55 0.00178
-24 0.06310 -56 0.00158
-25 0.05623 -57 0.00141
-26 0.05012 -58 0.00126
-27 0.04467 -59 0.00112
-28 0.03981 -60 0.00100
-29 0.03548 -61 0.00089
-30 0.03162 -62 0.00079
-31 0.02818 -63 0.00071
-32 0.02512 -64 mute
this ratiometric output can also be expressed as the ration of rl to ree (=rl/ree) so, as an example, the value of rl at a wiper setting of -21 db would be 0.08913 x ree.
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Calculate Ratiometric Outputs
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免费注册参加在线研讨会，学习如何分析、测量并最终解决音频系统的设计问题 (english only) 。
overviewthe ds1802 is a dual audio taper-potentiometer with logarithmic resistive characteristics over the device range. each potentiometer provides 65 wiper positions with a 1db increment per step and device mute with at least 90db of attenuation. table 1 shows the db output as a function of the potentiometer wiper setting.
table 1. ds1802 gain (db) as a function of wiper setting - resistance characteristics position output level (db)
0 0
1 -1
2 -2
3 -3
4 -4
5 -5
• •
• •
• •
63 -63
64 (mute) < -90
this chart only gives the output as a function of db attenuation with reference to 0db attenuation at the wiper 0 position. if the ratiometric output is desired, the ratio of the output signal relative to the input signal, a conversion must be made to convert db to a ratiometric attenuation value.
db attenuation is defined as 20 x log(vout/vin).
the desired ratiometric output is defined as:
rl/ree = rl/(rl + rh) = vout/vin
with rh = defined as the high-side of the ds1802, rl defined as the low side of the ds1802, ree defined as the end-to-end resistance, and vout and vin defined as the output and input signals, respectively, as shown in figure 1.
figure 1. ds1802 block diagram (one potentiometer shown).
if we know the db attenuation for a given potentiometer setting, we can calculate the ratiometric output by solving for vout/vin or:
the ratiometric output = inverse log10(db attenuation/20). if one wanted to calculate the output signal ratiometrically as a function of the input in a spreadsheet like excel, no function for the inverse log function exists. as the inverse log function of x can be calculated as 10x, in excel the power function can be used as follows: = (10)^(db/20), where db can be a value stored in another cell in the spreadsheet.
table 2 below summarizes the ratiometric outputs available for the ds1802. while this example is given for the ds1802, it may be used in calculations to determine the ratiometric output of any log potentiometer.
table 2. ratiometric output of the ds1802 as a function of db (wiper) setting db attenuation ratiometric output db attenuation ratiometric output
0 1.00000 -32 0.02512
-1 0.89125 -33 0.02239
-2 0.79433 -34 0.01995
-3 0.70795 -35 0.01778
-4 0.63096 -36 0.01585
-5 0.56234 -37 0.01413
-6 0.50119 -38 0.01259
-7 0.44668 -39 0.01122
-8 0.39811 -40 0.01000
-9 0.35481 -41 0.00891
-10 0.31623 -42 0.00794
-11 0.28184 -43 0.00708
-12 0.25119 -44 0.00631
-13 0.22387 -45 0.00562
-14 0.19953 -46 0.00501
-15 0.17783 -47 0.00447
-16 0.15849 -48 0.00398
-17 0.14125 -49 0.00355
-18 0.12589 -50 0.00316
-19 0.11220 -51 0.00282
-20 0.10000 -52 0.00251
-21 0.08913 -53 0.00224
-22 0.07943 -54 0.00200
-23 0.07079 -55 0.00178
-24 0.06310 -56 0.00158
-25 0.05623 -57 0.00141
-26 0.05012 -58 0.00126
-27 0.04467 -59 0.00112
-28 0.03981 -60 0.00100
-29 0.03548 -61 0.00089
-30 0.03162 -62 0.00079
-31 0.02818 -63 0.00071
-32 0.02512 -64 mute
this ratiometric output can also be expressed as the ration of rl to ree (=rl/ree) so, as an example, the value of rl at a wiper setting of -21 db would be 0.08913 x ree.
真正能够防盗的智能锁应该具备以下几大条件
使用Magic Packet远程唤醒单片机
详细解析FCoE协议
SpaceX原型机着陆数分钟后爆炸
欧普照明17年营业收入突破69.57亿元 同比增长27.03%
Calculate Ratiometric Outputs
无人机可以保护水下生物吗
一加5即将上市：国内唯一低调“不将就”的手机品牌新作，一加5你什么理由不去期待！
微雪电子圆形一体式电容指纹开发模块简介
17款新车加持 宝马集团依旧将坚持“2＋4”战略
Java中的SPI动态扩展（下）
兆易创新透露MCU出货量已经超4亿颗
中国联通"新起点,新征程—匠心网络万里行”活动正式拉开帷幕
呼吸灯有什么用_华为呼吸灯在哪设置
新松最新发布机器人的智能控制系统
risc-v架构如何发展？芯片公司是如何看待RISC-V？
发电机原理和电磁感应原理
台积电今年资本支出金额或创历史新高
华为数字能源打造新型电力系统能源基础设施
2020年全球芯片采购支出高达4498亿美元