Data Recorder

Posted on Feb 5, 2014

The Data Recorder (A3007) is a LWDAQ Device that decodes and recordes subcutaneous transmitter ( SCT ) messagess. The A3007 takes the signal generated by a demodulator such as the Demodulating Amplifier ( A3017 ) and determines when this signal contains a valid SCT message sequence. It stores messages in its 512-KByte memory and makes them availab

Data Recorder
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le to the LWDAQ. Figure: An A3007D in A3018C Enclosure. Auxilliary power sockets on top and right side are used to power RF circuits. The square logic chip is programmed throug the 8-way SIP connector. The RAM is on the right. Four indicator lamps are on the left, with the LWDAQ device socket. The discriminator comparator and RC circuits are on the bottom center, near the BNC plug that brings in the demodulated SCT signal. The A3007 is used in the Data Receiver ( A3018 ). The A3007A and A3007B were used in the Data Receiver ( A3010 ). These versions are obsolete. The A3007A was unreliable because it used a ring oscillator to generate timing for the upload to the LWDAQ driver. The A3007B was equipped with a 40-MHz crystal oscillator piggy-backed onto the logic chip. Both the A and B versions are obsolete. We added a 40-MHz oscillator to the A3007C, which is shown in page two of the schematic. The A3007D has a modified discriminator filter on its input, which gives superior message decoding. The A3007E fixes a severe bug in the firmware that generated bad messages in the presence of interference. S3007_2 : Second page of circuit diagram showing data clock oscillator, power distribution connectors, and indicator lamp logic. The A3007C used 10nF for C10, but in the A3007D we reduce C10 to 1nF so we can see poor reception as a reduction in intensity of D1. The A3007C used different values for the discriminator: R2=0 ©, C4=1nF,...

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