SSM2122 Analog Devices, SSM2122 Datasheet
SSM2122
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SSM2122 Summary of contents
Page 1
... This “dynamic range processor” consists of two VCAs and two level detectors (the SSM2122 consists of two VCAs only). These circuit blocks allow the user to logarithmically control the gain or attenuation of the signals presented to the level detectors depending on their magnitudes ...
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... ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the human body and test equipment and can discharge without detection. Although the SSM2120/SSM2122 features proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance degradation or loss of functionality ...
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... THD. 0.03 0.01 0.003 –20 a. VCA THD Performance vs. Gain (+10 dBV In/Out @ 1 kHz) –70 –80 –90 –20 b. VCA Noise vs. Gain (20 kHz Bandwidth) Figure 2. Typical THD and Noise Performance –3– SSM2120/SSM2122 V+ THRESH 1 CON OUT V– LOG THRESH 2 CON OUT 2 ...
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... SSM2120/SSM2122 TRIMMING THE VCAs The control feedthrough (CFT) pins are optional control feed- through null points. CFT nulling is usually required in applications such as noise gating and downward expansion. If trimming is not used, leave the CFT pins open. Trim Procedure 1. Apply a 100 Hz sine wave to the control point attenuator. ...
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... THRESHOLD CONTROL V T V– 39k CON CON IN OUT 1k 200 LOG AV 1.5M V– V– –5– SSM2120/SSM2122 ) and the value of REF I 333 REF for 11.28 ms 21.46 30.19 16.65 26.83 35.56 18 ...
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... SSM2120/SSM2122 In the noise gate, downward expander and compressor/limiter applications, this potentiometer will establish the onset of the control action. The sensitivity of the control action depends on the value For a positive unipolar control output add two diodes as shown in Figure 7a. This is useful in compressor/limiter applications. Figure 7b shows a typical response. ...
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... C/E –60 –80 Figure 11. Companding Noise Reduction with 2:1 Compression/Expansion Ratio Table II. Expander Only Output Signal Increase (dB) 22.67 30.00 33.33 35.00 36.00 37.33 38.00 40.00 –7– SSM2120/SSM2122 10pF –V C 36k 200 SIGNAL 2200pF OUTPUT +V V+ 200 C V+ 10k R E 39k |I ...
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... SSM2120/SSM2122 DYNAMIC FILTER Figure 12 shows a control circuit for a dynamic filter capable of single ended (nonencode/decode) noise reduction. Such circuits usually suffer from a loss of high frequency content at low signal levels because their control circuits detect the absolute amount of highs present in the signal. This circuit, however, measures wideband level as well as high frequency band level to produce a composite control signal combined in a 1:2 ratio respectively ...
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... Even in this system, however, a certain amount of mid- and high frequency components will be lost, especially during transients at very low signal levels. This circuit does not address low frequency noise such as “hum” and “rumble.” REV. C SSM2120/SSM2122 –10 – ...
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... SSM2120/SSM2122 R IN1 REC IN SIGNAL INPUT F 20Hz C C AV1 V– R IN2 REC 5Hz C C AV2 V– Figure 14. Dynamic Filter with Downward Expander DYNAMIC FILTER WITH DOWNWARD EXPANDER A composite single-ended noise reduction system can be realized by a combination of dynamic filtering and a downward expander. As shown in Figure 14, the output from the wideband detector can also be connected to the +V second VCA which is connected in series with the sliding filter ...
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... Since this device is a pinout option of the SSM2120, the VCAs will behave exactly as described earlier in the VCA section. The SSM2122 can also be used with two or more op amps to implement complex voltage-controlled filter functions. Biquad and state-variable two-pole filters offering low pass, bandpass and high pass outputs can be realized ...
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... SSM2120/SSM2122 0.210 (5.33) 0.160 (4.06) 0.115 (2.93) 0.210 (5.33) MAX 0.160 (4.06) 0.115 (2.93) OUTLINE DIMENSIONS Dimensions shown in inches and (mm). 16-Pin Plastic DIP (N-16) 0.840 (21.33) 0.745 (18.93 0.280 (7.11) 0.240 (6.10 0.325 (8.25) 0.060 (1.52) 0.300 (7.62) PIN 1 0.015 (0.38) MAX 0 ...