SSM-2120 Analog, SSM-2120 Datasheet
SSM-2120
Related parts for SSM-2120
SSM-2120 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 ...
Page 2
... 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 ...
Page 3
... WAVE RECTIFIER 2V FULL REC IN 2 WAVE OUTPUT 2 RECTIFIER 2V Figure 1. SSM2120 Block Diagram VCA PERFORMANCE Figures 2a and 2b show the typical THD and noise performance of the VCAs over 20 dB gain/attenuation. Full Class A operation provides very low THD. 0.03 0.01 0.003 –20 a. VCA THD Performance vs. Gain (+10 dBV In/Out @ 1 kHz) – ...
Page 4
... In this case the signal masks control feedthrough. This trim is ineffective for voltage-controlled filter applications. LEVEL DETECTION CIRCUITS The SSM2120 contains two independent level detection circuits. Each circuit contains a wide dynamic range full-wave rectifier, logging circuit and a unipolar drive amplifier. These circuits will accurately detect the input signal level over a 100 dB range from peak-to-peak ...
Page 5
... Step 40 dB Step 50 dB Step 60 dB Step APPLICATIONS The following applications for the SSM2120 use both the VCAs and level detectors in conjunction to assimilate a variety of 50ms functions. The first section describes the arrangement of the threshold control in each control circuit configuration. These control ...
Page 6
... 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. ...
Page 7
... C/E –40 . 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 | REC IN 1k LOG AV 1µF 4.7M V– ...
Page 8
... 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 ...
Page 9
... 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 – ...
Page 10
... 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 ...
Page 11
... 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 ...
Page 12
... 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 0.130 (3.30) MIN 0.022 (0.558) 0.100 0.070 (1.77) SEATING PLANE (2.54) 0.045 (1.15) 0.014 (0.356) BSC ...